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LXT9883/9863 advanced 10/100 unmanaged repeater datasheet the LXT9883 is an advanced, 3.3v, 8-port 10/100 repeater. the LXT9883 is compatible with previous generations of intel repeaters from the lxt980 and lxt918 families. eight ports directly support 100base-tx/10base-t copper media. two additional media independent interface (mii) ports (10/100mbps selectable) connect to media access controllers (macs) for bridge/switch applications. the lxt9863 offers the same features and functionality in a six-port device. this data sheet uses the singular designation ?lxt98x3? to refer to both devices. the lxt98x3 provides auto-negotiation with parallel detection for the phy ports. the lxt98x3 provides two internal repeater state machines?one operating at 10 mbps and one at 100 mbps. once configured, the lxt98x3 automatically connects each port to the appropriate repeater. the lxt98x3 also provides two inter-repeater backplanes (irbs) for expansion ? one operating at 10 mbps and one at 100 mbps. up to 240 twisted-pair and mii ports can logically be combined into one repeater. product features six or eight 10/100 ports with integrated twisted-pair phys including integrated filters. two 10/100 miis for bridging. independent segments for 10mbps and 100 mbps operation. cascadable inter-repeater backplanes (irbs), with option for 5v stacking compatibility. integrated led drivers with user-selectable modes. available in 208-pin qfp package. operating temperature range: 0-70 c, ambient. as of january 15, 2001, this document replaces the level one document order number: 249115-003 LXT9883/lxt9863 ? advanced 10/100 unmanaged repeater . august 2001
2 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 information in this document is provided in connection with intel ? products. no license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document. except as provided in intel?s terms and conditions of sale for such products, inte l assumes no liability whatsoever, and intel disclaims any express or implied warranty, relating to sale and/or use of intel products including liabil ity or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property righ t. intel products are not intended for use in medical, life saving, or life sustaining applications. intel may make changes to specifications and product descriptions at any time, without notice. designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined." int el reserves these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them. the LXT9883/9863 may contain design defects or errors known as errata which may cause the product to deviate from published spe cifications. current characterized errata are available on request. contact your local intel sales office or your distributor to obtain the latest specifications and before placing your product o rder. copies of documents which have an ordering number and are referenced in this document, or other intel literature may be obtaine d by calling 1-800-548-4725 or by visiting intel?s website at http://www.intel.com. copyright ? intel corporation, 2001 *third-party brands and names are the property of their respective owners.
datasheet 3 document #: 249115 revision #: 003 rev. date: 08/07/01 contents contents 1.0 block diagram ............................................................................................................................... 7 2.0 pin assignments and signal descriptions ................................................................................. 8 3.0 functional description ................................................................................................................ 16 3.1 introduction ................................................................................................................ ......... 16 3.2 port configuration.......................................................................................................... ..... 17 3.2.1 auto-negotiation .................................................................................................... 17 3.2.2 link establishment and port connection ............................................................... 18 3.3 interface descriptions ...................................................................................................... ... 18 3.3.1 twisted-pair interface............................................................................................ 18 3.3.2 media independent interface ................................................................................. 18 3.4 repeater operation .......................................................................................................... .. 19 3.4.1 100 mbps repeater operation .............................................................................. 19 3.4.2 10 mbps repeater operation ................................................................................ 20 3.5 requirements ................................................................................................................ ..... 20 3.5.1 power..................................................................................................................... 20 3.5.2 clock ..................................................................................................................... .21 3.5.3 bias resistor.......................................................................................................... 21 3.5.4 reset ..................................................................................................................... 21 3.5.5 irb bus pull-ups.................................................................................................... 21 3.6 led operation ............................................................................................................... ..... 21 3.6.1 leds at start-up .................................................................................................... 21 3.6.2 led event stretching ............................................................................................ 22 3.6.3 serial led interface............................................................................................... 22 3.6.4 serial shifting......................................................................................................... 22 3.6.4.1 serial led signals ................................................................................. 23 3.6.4.2 activity graph leds............................................................................... 23 3.6.5 direct drive leds .................................................................................................. 24 3.6.6 led modes ............................................................................................................ 24 3.6.6.1 led mode 1 ........................................................................................... 25 3.6.6.2 led mode 2 ........................................................................................... 25 3.6.6.3 led mode 3 ........................................................................................... 26 3.6.6.4 led mode 4 ........................................................................................... 28 3.7 irb operation ............................................................................................................... ...... 28 3.7.1 irb signal types ................................................................................................... 28 3.7.2 10m-only operation .............................................................................................. 29 3.7.2.1 mac irb access ................................................................................... 29 3.7.3 lxt98x/91x/98xx compatibility ............................................................................. 29 3.8 mii port operation .......................................................................................................... .... 31 3.8.1 preamble handling ................................................................................................ 31 4.0 application information .............................................................................................................. 32 4.1 general design guidelines ................................................................................................. 32 4.2 power and ground............................................................................................................ .. 33 4.2.1 supply filtering ...................................................................................................... 33 4.2.2 ground noise......................................................................................................... 33
contents 4 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.3 power and ground plane layout considerations.................................................. 33 4.2.4 chassis ground ..................................................................................................... 34 4.2.5 the rbias pin....................................................................................................... 34 4.2.6 mii terminations .................................................................................................... 35 4.2.7 twisted-pair interface............................................................................................ 36 4.2.7.1 magnetics information............................................................................ 36 4.2.8 clock..................................................................................................................... .37 4.2.9 led circuits........................................................................................................... 39 4.2.9.1 direct drive leds .................................................................................. 39 4.2.9.2 led pins multiplexed with configuration inputs .................................... 39 4.2.9.3 serial leds ............................................................................................ 40 4.3 inter-repeater backplane compatibility ............................................................................. 41 4.3.1 local backplane ? 3.3v only ................................................................................. 41 4.3.2 stack backplane ? 3.3v or 5v ............................................................................... 41 4.3.2.1 3.3v-only stacks ................................................................................... 41 4.3.2.2 for 5v backwards stackability .............................................................. 41 4.3.2.3 3.3v and 5.0v stacking boards cannot be mixed ................................ 41 5.0 test specifications ...................................................................................................................... 44 6.0 mechanical specifications .......................................................................................................... 56 figures 1 lxt98x3 block diagram......................................................................................................... ...... 7 2 LXT9883 pin assignments ....................................................................................................... .... 8 3 typical LXT9883 repeater architecture .................................................................................... 17 4 mii interface................................................................................................................. ............... 19 5 serial led shift loading ..................................................................................................... ...... 22 6 serial led port signaling ..................................................................................................... ...... 23 7 100m irb connection ........................................................................................................... ..... 29 8 irb block diagram ............................................................................................................ ........ 30 9 LXT9883 mii operation ......................................................................................................... ..... 32 10 power and ground connections ................................................................................................ 3 5 11 typical twisted-pair port interface and power supply filtering ................................................ 38 12 typical reset circuit ....................................................................................................... ........... 38 13 led circuits - direct drive & multiplexed configuration inputs .................................................. 39 14 serial led circuit ........................................................................................................... ............ 40 15 100m backplane connection between lxt98x and lxt98x3 ................................................... 42 16 typical 100 mbps irb implementation ...................................................................................... 43 17 typical 10 mbps irb implementation ........................................................................................ 43 18 100 mbps tp port-to-port delay timing..................................................................................... 48 19 100base-tx mii-to-tp port timing .......................................................................................... 49 20 100base-tx tp-to-mii timing ................................................................................................. 50 21 10base-t mii-to-tp timing ................................................................................................... ... 51 22 10base-t tp-to-mii port timing .............................................................................................. 52 23 100 mbps tp-to-irb timing ................................................................................................... ... 53 24 10 mbps tp-to-irb timing .................................................................................................... .... 54 25 10 mbps irb-to-tp port timing ............................................................................................... .55 26 lxt98x3 package specifications .............................................................................................. 56
datasheet 5 document #: 249115 revision #: 003 rev. date: 08/07/01 contents tables 1 mii #1 signal descriptions .................................................................................................... ........ 9 2 mii #2 signal descriptions .................................................................................................... ...... 10 3 inter-repeater backplane signal descriptions ........................................................................... 11 4 twisted-pair port signal descriptions ........................................................................................ 1 3 5 led signal descriptions ....................................................................................................... ...... 14 6 power supply and indication signal descriptions ...................................................................... 15 7 miscellaneous signal descriptions ............................................................................................. 16 8 serial led port bit stream .................................................................................................... ..... 23 9 actgled display modes ......................................................................................................... .24 10 led terms.................................................................................................................... .............. 24 11 led mode 1 indications....................................................................................................... ....... 25 12 led mode 2 indications....................................................................................................... ....... 26 13 led mode 3 indications....................................................................................................... ....... 27 14 led mode 4 indications....................................................................................................... ....... 28 15 cascading and stacking connections ........................................................................................ 30 16 irb signal details........................................................................................................... ............ 31 17 lxt98x3 magnetics specifications............................................................................................. 36 18 oscillator manufacturers..................................................................................................... ........ 37 19 absolute maximum ratings ..................................................................................................... ... 44 20 operating conditions ......................................................................................................... ......... 44 21 input system clock1 requirements ........................................................................................... 44 22 i/o electrical characteristics............................................................................................... ........ 45 23 100 mbps irb electrical characteristics..................................................................................... 4 5 24 10 mbps irb electrical characteristics....................................................................................... 46 25 100base-tx transceiver electrical characteristics ................................................................. 47 26 10base-t transceiver electrical characteristics...................................................................... 47 27 100 mbps tp port-to-port delay timing parameters ................................................................. 48 28 100base-tx mii-to-tp port timing parameters ....................................................................... 49 29 100base-tx tp-to-mii timing parameters ............................................................................... 50 30 10base-t mii-to-tp timing parameters ................................................................................... 51 31 10base-t tp-to-mii port timing parameters............................................................................ 52 32 100 mbps tp-to-irb timing parameters1.................................................................................. 53 33 10 mbps tp-to-irb timing parameters1.................................................................................... 54 34 10 mbps irb-to tp port timing parameters .............................................................................. 55
contents 6 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 revision history date revision page description august 2001 003 44 modify the absolute maximum ratings supply voltage value to 4.0v. february 2001 002 21, 37 modified clock requirements language. 21 replaced tbd value under reset to 3.15v. 33 replaced tbds in fourth para under supply filtering to 1000 ma and 1500 ma. 36 replaced tbds in fourth bullet under twisted-pair interface to 1000 ma and 1500 ma. 37 modified oscillator manufacturers table 43 typical 100 mbps irb implementation table: modified note 2 (replaced ? fps/ = 0 ? with ? fps/ 0. ? 43 typical 10 mbps irb implementation table: modified note 2 (replaced ? fps/ = 0 ? with ? fps/ 0. ? 44 absolute maximum ratings table: replaced tbd for supply voltage under max to 3.45. deleted operating temperature lines and values. 44 operating conditions table: for power consumption: removed auto-negotiation values. changed description and values for 8- and 6-port active.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 7 document #: 249115 revision #: 003 rev. date: 08/07/01 1.0 block diagram figure 1. lxt98x3 block diagram 10base-t repeater 100base-x repeater serial led drivers 10/100 phy 1 10 mbps backplane 100 mbps backplane port switching logic 10m irb 100m irb port & mgmt status indicators tx_i/o 10/100 phy 2 tx_i/o 10/100 phy 3 tx_i/o 10/100 phy 4 tx_i/o 10/100 phy 5 tx_i/o 10/100 phy 6 tx_i/o 10/100 phy 7 tx_i/o 10/100 phy 8 tx_i/o mii 1 mii_i/o mii 2 mii_i/o
LXT9883/9863 ? advanced 10/100 unmanaged repeater 8 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 2.0 pin assignments and signal descriptions figure 2. LXT9883 pin assignments package topside markings marking definition part # LXT9883 is the unique identifier for this product family. rev # identifies the particular silicon ? stepping ? (refer to specification update for additional stepping information.) lot # identifies the batch. fpo # identifies the finish process order. 52...........n/c 51...........n/c 50...........ir100clk 49...........ir100dat4 48...........ir100dat3 47...........vcc 46...........gnd 45...........ir100dat2 44...........ir100dat1 43...........ir100dat0 42........... ir 100dv 41........... ir 100den 40........... ir 100col 39...........comp_sel 38........... ir 100sngl 37........... ir 100cfsbp 36........... ir 100cfs 35...........mii1_rxd3 34...........mii1_rxd2 33...........n/c 32 ..........mii1_rxd1 31...........mii1_rxd0 30...........mii1_rxdv 29...........mii1_rxclk 28...........vcc 27...........gnd 26...........mii1_rxer 25...........n/c 24...........mii1_txer 23...........mii1_txclk 22...........mii1_txen 21...........mii1_txd0 20...........mii1_txd1 19...........mii1_txd2 18...........mii2_spd 17...........mii1_txd3 16...........vcc 15...........gnd 14...........mii1_col 13...........mii1_crs 12...........ir10clk 11...........ir10dat 10........... ir10ena 9.............mii1_spd 8.............vcc 7............. gnd 6............. ir10den 5............. ir10cfsbp 4............. ir10colbp 3............. ir10col 2............. ir10cfs 1............. gnd reset ....... 53 clk25....... 54 n/c....... 55 n/c....... 56 n/c....... 57 n/c....... 58 n/c....... 59 n/c....... 60 vcc....... 61 gnd....... 62 n/c....... 63 n/c....... 64 n/c....... 65 n/c....... 66 n/c....... 67 n/c....... 68 n/c....... 69 n/c....... 70 n/c....... 71 fps ....... 72 n/c....... 73 vcc....... 74 gnd....... 75 vcc....... 76 vcc....... 77 rps_fault ....... 78 rps_pres....... 79 macactive....... 80 holdcol....... 81 ledclk....... 82 leddat....... 83 ledlat....... 84 vcc....... 85 gnd....... 86 ort1_led3....... 87 ort1_led2....... 88 ort1_led1....... 89 gnd....... 90 ort2_led3....... 91 ort2_led2....... 92 ort2_led1....... 93 gnd....... 94 ort3_led3....... 95 ort3_led2....... 96 ort3_led1....... 97 gnd....... 98 ort4_led3....... 99 ort4_led2....... 100 ort4_led1....... 101 rbias....... 102 gnd....... 103 tpip1....... 104 208 ....... mii2_rxd3 207 ....... mii2_rxd2 206 ....... mii2_rxd1 205 ....... mii2_rxd0 204 ....... mii2_rxdv 203 ....... mii2_rxclk 202 ....... mii2_rxer 201 ....... n/c 200 ....... vcc 199 ....... gnd 198 ....... n/c 197 ....... mii2_txer 196 ....... mii2_txclk 195 ....... mii2_txen 194 ....... mii2_txd0 193 ....... mii2_txd1 192 ....... mii2_txd2 191 ....... mii2_txd3 190 ....... vcc 189 ....... gnd 188 ....... mii2_col 187 ....... mii2_crs 186 ....... co l100_led 185 ....... ledsel1/col10_led 184 ....... ledsel0/act100_led 183 ....... autoblink /act10_led 182 ....... n/c 181 ....... gnd 180 ....... vcc 179 ....... gnd 178 ....... n/c 177 ....... vcc 176 ....... port8_led1* 175 ....... port8_led2*/ledabgsel 174 ....... port8_led3* 173 ....... vcc 172 ....... gnd 171 ....... port7_led1* 170 ....... port7_led2* 169 ....... port7_led3* 168 ....... gnd 167 ....... port6_led1 166 ....... port6_led2 165 ....... port6_led3 164 ....... gnd 163 ....... port5_led1 162 ....... port5_led2 161 ....... port5_led3 160 ....... txslew_1 159 ....... txslew_0 158 .......gnd 157 .......*tpip8 tpin1 .......105 vcc r .......106 tpop1 .......107 tpon1 .......108 gnd .......109 tpon2 .......110 tpop2 .......111 vcc t .......112 vcc r .......113 tpin2 .......114 tpip2 .......115 gnd .......116 gnd .......117 tpip3 .......118 tpin3 .......119 vcc r .......120 tpop3 .......121 tpon3 .......122 gnd .......123 tpon4 .......124 tpop4 .......125 vcc t .......126 vcc r .......127 tpin4 .......128 tpip4 .......129 gnd .......130 gnd .......131 tpip5 .......132 tpin5 .......133 vcc r .......134 vcc t .......135 tpop5 .......136 tpon5 .......137 gnd .......138 tpon6 .......139 tpop6 .......140 vcc r .......141 tpin6 .......142 tpip6 .......143 gnd .......144 gnd .......145 *tpip7 .......146 *tpin7 .......147 vcc r .......148 vcc t .......149 *tpop7 .......150 *tpon7 .......151 gnd .......152 *tpon8 .......153 *tpop8 .......154 vcc r .......155 *tpin8 .......156 * indicates LXT9883-only pins. tp ports 7 and 8 are not available on lxt9863 LXT9883 xx xxxxxx xxxxxxxx part # lot # fpo # part # lot # fpo # rev #
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 9 document #: 249115 revision #: 003 rev. date: 08/07/01 table 1. mii #1 signal descriptions pin symbol type 1, 2 description 9 mii1_spd i pu speed select - mii 1. this signal is sensed at power up, hardware reset, and software reset. selects operating speed of the respective mii (mac) interface. high = 100 mbps. low = 10 mbps. 31 32 34 35 mii1_rxd0 mii1_rxd1 mii1_rxd2 mii1_rxd3 o receive data - mii 1. the lxt98x3 transmits received data to the controller on these outputs. data is driven on the falling edge of mii1_rxclk. 30 mii1_rxdv o receive data valid - mii 1. active high signal, synchronous to mii1_rxclk, indicates valid data on mii1_rxd<3:0>. 29 mii1_rxclk o receive clock - mii 1. mii receive clock for expansion port. this is a 2.5 or 25 mhz clock derived from the clk25 input (refer to table 7 on page 16 ). 26 mii1_rxer o receive error - mii 1. active high signal, synchronous to mii1_rxclk, indicates invalid data on mii1_rxd<3:0>. 24 mii1_txer i transmit error - mii 1. mii1_txer is a 100m-only signal. the mac asserts this input when an error has occurred in the transmit data stream. the lxt98x3 responds by sending ? invalid code symbols ? on the line. 23 mii1_txclk o transmit clock - mii 1. this is a 2.5 or 25 mhz clock derived from the clk25 input (refer to table 7 on page 16 ). 22 mii1_txen i transmit enable - mii 1. external controllers drive this input high to indicate data is transmitted on the mii1_txd<3:0> pins. ground this input if unused. 21 20 19 17 mii1_txd0 mii1_txd1 mii1_txd2 mii1_txd3 i transmit data - mii 1. external controllers use these inputs to transmit data to the lxt98x3. the lxt98x3 samples mii1_txd<3:0> on the rising edge of mii1_txclk, when mii1_txen is high. 14 mii1_col o collision - mii 1. the lxt98x3 drives this signal high to indicate a collision occurred. 13 mii1_crs o carrier sense - mii 1. active high signal indicates lxt98x3 is transmitting or receiving. 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 10 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 table 2. mii #2 signal descriptions pin symbol type 1, 2 description 18 mii2_spd i pu speed select - mii 2. this signal is sensed at power up, hardware reset, and software reset. selects operating speed of the respective mii (mac) interface. high = 100 mbps. low = 10 mbps. 205 206 207 208 mii2_rxd0 mii2_rxd1 mii2_rxd2 mii2_rxd3 o receive data - mii 2. the lxt98x3 transmits received data to the controller on these outputs. data is driven on the falling edge of mii2_rxclk. 204 mii2_rxdv o receive data valid - mii 2. active high signal, synchronous to mii2_rxclk, indicates valid data on mii2_rxd<3:0>. 203 mii2_rxclk o receive clock - mii 2. mii receive clock for expansion port. this is a 2.5 or 25 mhz clock derived from the clk25 input (refer to table 7 on page 16 ). 202 mii2_rxer o receive error - mii 2. active high signal, synchronous to mii2_rxclk, indicates invalid data on mii2_rxd<3:0>. 197 mii2_txer i transmit error - mii 2. mii2_txer is a 100m-only signal. the mac asserts this input when errors occurs in the transmit data stream. the lxt98x3 sends ? invalid code symbols ? on the line. 196 mii2_txclk o transmit clock - mii 2. this is a 2.5 or 25 mhz clock derived from the clk25 input (refer to table 7 on page 16 ). 195 mii2_txen i transmit enable - mii 2. external controllers drive this input high to indicate data is transmitted on the mii2_txd<3:0> pins. ground this input if unused. 194 193 192 191 mii2_txd0 mii2_txd1 mii2_txd2 mii2_txd3 i transmit data - mii 2. external controllers use these inputs to transmit data to the lxt98x3. the lxt98x3 samples mii2_txd<3:0> on the rising edge of mii2_txclk, when mii2_txen is high. 188 mii2_col o collision - mii 2. the lxt98x3 drives this signal high to indicate a collision occurred. 187 mii2_crs o carrier sense - mii 2. active high signal indicates lxt98x3 is transmitting or receiving. 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 11 document #: 249115 revision #: 003 rev. date: 08/07/01 table 3. inter-repeater backplane signal descriptions pin symbol type 1, 2 description common irb signals 39 comp_sel ai compatibility mode select. 3.3v on this pin causes the ircfsbp signals to operate in 3.3v only mode. 5v on this pin causes the ir100cfsbp or ir10cfsbp signals to operate in 5v backwards compatibility mode with lxt98x devices. 100 mbps irb signals 36 ir100cfs 3 a i/o od 100 mbps irb collision force sense. a three-level signal that determines number of active ports on the ? logical ? repeater. high level (3.3v) indicates no ports active; mid level (approx. 1.6v) indicates one port active; low level (0v) indicates more than one port active, resulting in a collision. this signal requires a 215 ? pull-up resistor, and connects between ics on the same board. 37 ir100cfsbp a i/o od 100 mbps irb collision force sense - backplane. this three-level signal functions the same as ir100cfs ; however, it connects between ics with fps = 0, on different boards. ir100cfsbp requires a single 91 ? pull-up resistor in each stack. this signal can be set in either 5v or 3.3v modes by the comp_sel pin. 38 ir100sngl i/o schmitt pu 100 mbps single driver state. this active low signal is asserted by the device with fps = 0 when a packet is received from one or more ports. do not connect this signal between boards. 40 ir100col i/o schmitt pu 100 mbps multiple driver state. this active low signal is asserted by the device with fps = 0 when a packet is being received from more than one port (collision). do not connect this signal between boards. 41 ir100den o od 100 mbps irb driver enable. this output provides directional control for an external bidirectional transceiver (74lvt245) used to buffer the 100 mbps irb in multi-board applications. it must be pulled up by a 330 ? resistor. when there are multiple devices on one board, tie all ir100den outputs together. if ir100den is tied directly to the dir pin on a 74lvt245, attach the on-board ir100dat, ir100clk, and ir100dv signals to the ? b ? side of the 74lvt245, and connect the off-board signals to the ? a ? side of the 74lvt245. 42 ir100dv i/o schmitt od pu 100 mbps irb data valid. this active low signal indicates port activity on the repeater. ir100dv frames the clock and data of the packet on the backplane. this signal requires a 300 ? pull-up resistor. 43 44 45 48 49 ir100dat0 ir100dat1 ir100dat2 ir100dat3 ir100dat4 i/o tri-state schmitt pu 100 mbps irb data. these bidirectional signals carry 5-bit data on the 100 mbps irb. data is driven on the falling edge and sampled on the rising edge of ir100clk. buffer these signals between boards. 50 ir100clk i/o tri-state schmitt pd 100 mbps irb clock. this bidirectional, non-continuous, 25 mhz clock is recovered from received network traffic. schmitt triggering is used to increase noise immunity. this signal must be pulled to vcc when idle. one 1 k ? pull-up resistor on both sides of a 74lvt245 buffer is recommended. 1. i = input, o = output, i/o = input/output, d = digital, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. even if the irb is not used, required pull-up resistors must be installed as listed above. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated. 3. ir100cfs is not 5v tolerant. 4. ir10cfs is not 5v tolerant.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 12 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 10 mbps irb signals 11 ir10dat i/o od pd 10 mbps irb data. this bidirectional signal carries data on the 10 mbps irb. data is driven and sampled on the rising edge of the corresponding irclk. this signal must be pulled high by a 330 ? resistor. buffer this signal between boards. 12 ir10clk i/o tri-state schmitt pd 10 mbps irb clock. this bidirectional, non-continuous, 10 mhz clock is recovered from received network traffic. during idle periods, the output is high-impedance. schmitt triggering is used to increase noise immunity. 6 ir10den o od 10 mbps irb driver enable. this output provides directional control for an external bidirectional transceiver (74lvt245) used to buffer the irbs in multi-board applications. it must be pulled up by a 330 ? resistor. when there are multiple devices on one board, tie all ir10den outputs together. if ir10den is tied directly to the dir pin on a 74lvt245, attach the on-board ir10dat, ir10clk and ir10ena signals to the ? b ? side of the 74lvt245, and connect the off-board signals to the ? a ? side of the 74lvt245. 10 ir10ena i/o od pu 10 mbps irb enable. this active low output indicates carrier presence on the irb. a 330 ? pull-up resistor is required to pull the ir10ena output high when the irb is idle. when there are multiple devices, tie all ir10ena outputs together. buffer these signals between boards. 3 ir10col i/o od pu 10 mbps irb collision. this output is driven low to indicate a collision occurred on the 10 mbps segment. a 330 ? resistor is required on each board to pull this signal high when there is no collision. do not connect between boards and do not buffer. 4 ir10colbp i/o od 10 mbps irb collision - backplane. this active low output has the same function as ir10col , but is used between boards. attach this signal only from the device with fps = 0 to the backplane or connector, without buffering . the output must be pulled up by one 330 ? resistor per stack. 2 ir10cfs 4 a, i/o od 10 mbps irb collision force sense. this three-state analog signal indicates transmit collision when driven low. ir10cfs requires a 215 ? , 1% pull-up resistor. do not connect this signal between boards and do not buffer. 5 ir10cfsbp a i/o od note: 10 mbps irb collision force sense - backplane. functions the same as ir10cfs , but connects between boards. attach this signal only from the device with fps = 0 to the backplane or connector, without buffering . this signal requires one 330 ? , 1% pull-up resistor per stack. this signal can be set for 5v or 3.3v modes by the comp_sel pin. 80 macactive i pd note: mac active. active high input allows external asics to participate in 10 mbps irb. driving data onto the irb requires the external asic assert macactive high for one clock cycle, then assert ir10ena low. asic monitors ir10col (active low) for collision. by using macactive, the repeater ? not the mac ? drives the three-level ir10cfs pin. 81 holdcol i/o pd note: hold collision for 10 mbps mode. this active high signal is driven by the device with fps = 0 to extend a non-local transmit collision to other devices on the same board. do not attach the holdcol signals from different boards together. table 3. inter-repeater backplane signal descriptions (continued) pin symbol type 1, 2 description 1. i = input, o = output, i/o = input/output, d = digital, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. even if the irb is not used, required pull-up resistors must be installed as listed above. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated. 3. ir100cfs is not 5v tolerant. 4. ir10cfs is not 5v tolerant.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 13 document #: 249115 revision #: 003 rev. date: 08/07/01 table 4. twisted-pair port signal descriptions pin symbol type 1 description 107, 108 111, 110 121, 122 125, 124 136, 137 140, 139 150, 151 154, 153 tpop1, tpon1 tpop2, tpon2 tpop3, tpon3 tpop4, tpon4 tpop5, tpon5 tpop6, tpon6 tpop7, tpon7 tpop8, tpon8 caution: ao twisted-pair outputs - ports 1 through 8. these pins are the positive and negative outputs from the respective ports ? twisted-pair line drivers. for unused ports, these pins can be left open. 104, 105 115, 114 118, 119 129, 128 132, 133 143, 142 146, 147 157, 156 tpip1, tpin1 tpip2, tpin2 tpip3, tpin3 tpip4, tpin4 tpip5, tpin5 tpip6, tpin6 tpip7, tpin7 tpip8, tpin8 caution: ai twisted-pair inputs - ports 1 through 8. these pins are the positive and negative inputs to the respective ports ? twisted-pair receivers. for unused ports, tie together with 100 ? resistors and float. 160 159 txslew_1 txslew_0 i pd tx output slew controls 0 and 1 . these pins select the tx output slew rate (rise and fall time) as follows: txslew_1 txslew_0 slew rate (rise and fall time) 0 0 2.5 ns 0 1 3.1 ns 1 0 3.7 ns 1 1 4.3 ns 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, ao = analog output, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. nc = no clamp. pad does not clamp input in the absence of power.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 14 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 table 5. led signal descriptions pin symbol type 1, 2 description 184 185 ledsel0 ledsel1 i 3 o - od/os led mode select - input. see note 3 in footer below. 00 = mode 1, 01 = mode 2, 10 = mode 3, 11 = mode 4 these pins are shared with the ledact100, ledcol10 outputs. 175 ledabgsel i 3 o - od/os led activity bar graph mode select - input. see note 2 in footer below. 0 = base-10 mode, 1 = base-2 mode refer to "activity graph leds ? on page 23. this pin is shared with the port8_led2 output. 183 autoblink i 3 o - od/os led blink mode select - input. see note 3 in footer below. 0 = auto blink on, 1 = auto blink off this pin is shared with the ledact100, ledcol10 outputs. 83 leddat o led data . serial data stream that is shifted into external serial-to-parallel led drivers. see "serial led interface ? on page 22.. 84 ledlat o led latch . parallel load clock for external serial-to-parallel led drivers. see "serial led interface ? on page 22.. 82 ledclk o led clock . serial data stream clock for external serial-to-parallel led drivers. see "serial led interface ? on page 22.. 176 171 167 163 101 97 93 89 port8_led1 port7_led1 port6_led1 port5_led1 port4_led1 port3_led1 port2_led1 port1_led1 o od led driver 1 - ports 1 through 8 . programmable led driver. active low. see "direct drive leds ? on page 24.. port8_led1 must be pulled high via a 100 ? 500 k ? resistor if led circuit not used. 175 170 166 162 100 96 92 88 port8_led2 port7_led2 port6_led2 port5_led2 port4_led2 port3_led2 port2_led2 port1_led2 o od led driver 2 - ports 1 through 8 . programmable led driver. active low. see "direct drive leds ? on page 24.. the port8_led2 pin is shared with the ledabgsel configuration input. 174 169 165 161 99 95 91 87 port8_led3 port7_led3 port6_led3 port5_led3 port4_led3 port3_led3 port2_led3 port1_led3 o od led driver 3 - ports 1 through 8 . programmable led driver. active low. see "direct drive leds ? on page 24.. port8_led3 must be pulled high via a 100 ? 500 k ? resistor if led circuit not used. 185 col10_led i o - od/os 10m collision led driver . active output indicates collision on 10m segment. this pin is shared with the ledsel1 configuration input. 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. even if the irb is not used, required pull-up resistors must be installed as listed above. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated. 3. input must be static; refer to "led pins multiplexed with configuration inputs ? on page 39. for information on pin use.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 15 document #: 249115 revision #: 003 rev. date: 08/07/01 186 col100_led i o - od/os 100m collision led driver . active output indicates collision on 100m segment. 183 act10_led i o - od/os 10m activity led driver . active output indicates activity on 10m segment. this pin is shared with the autoblink configuration input (refer to note 3 below). 184 act100_led i o - od/os 100m activity led driver . active output indicates activity on 100m segment. this pin is shared with the ledsel0 configuration input (refer to note 3 below). table 6. power supply and indication signal descriptions pin symbol type 1, 2 description 8, 16, 28, 47, 61, 74, 76, 77, 85, 173, 177, 180, 190, 200 vcc - power supply inputs. each of these pins must be connected to a common +3.3 vdc power supply. a de-coupling capacitor to digital ground should be supplied for every one of these pins. 106, 113, 120, 127, 134, 141, 148, 155 vccr - analog supply inputs - receive. each of these pins must be connected to a common +3.3 vdc power supply. a de-coupling capacitor to gnd should be supplied for every one of these pins. use ferrite beads to create a separate analog vcc plane. 112, 126, 135, 149 vcct - analog supply inputs - transmit. each of these pins must be connected to a common +3.3 vdc power supply. a de-coupling capacitor to gnd should be supplied for every one of these pins. use ferrite beads to create a separate analog vcc plane. 1, 7, 15, 27, 46, 62, 75, 86, 90, 94, 98, 103, 109, 116, 117, 123, 130, 131, 138, 144, 145, 152, 158, 164, 168, 172, 179, 181, 189, 199 gnd - ground. connect each of these pins to system ground plane. 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated. table 5. led signal descriptions (continued) pin symbol type 1, 2 description 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. even if the irb is not used, required pull-up resistors must be installed as listed above. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated. 3. input must be static; refer to "led pins multiplexed with configuration inputs ? on page 39. for information on pin use.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 16 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 3.0 functional description 3.1 introduction as a fully integrated ieee 802.3 compliant repeater capable of 10 mbps and 100 mbps operation, the lxt98x3 is a versatile device allowing great flexibility in ethernet design solutions. figure 3 shows a typical application. refer to "application information? on page 32. for specific circuit implementations. 102 rbias a rbias. used to provide bias current for internal circuitry. the 100 a bias current is provided through an external 22.1 k ?, 1% resistor to gnd. 79 rps_pres i pd redundant power supply present. active high input indicates presence of redundant power supply. tie low if not used. 78 rps_fault i pu redundant power supply fault. active low input indicates redundant power supply fault. the state of this input is reflected in the rps_led output (refer to led section). tie high if not used. table 7. miscellaneous signal descriptions pin symbol type 1, 2 description 53 reset i schmitt reset. this active low input causes internal circuits, state machines and counters to reset (address tracking registers do not reset). on power-up, devices should not be brought out of reset until the power supply stabilizes to 3.3v. when there are multiple devices, it is recommended all be supplied by a common reset driven by an ? ls14 or similar device. 54 clk25 i schmitt 25 mhz system clock. refer to table 21 on page 44. 72 fps i ttl first position select. in multi-chip configurations, this pin identifies one device on each board that drives the holdcol signal to extend non-local collisions to other devices on the board. set low for first device on the pcb. set high for all other devices on the pcb. 25, 33, 51, 52, 55-60, 63-71, 73, 178, 182, 198, 201 n/c - no connects. leave these pins unconnected. 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated. table 6. power supply and indication signal descriptions (continued) pin symbol type 1, 2 description 1. i = input, o = output, i/o = input/output, d = digital, a = analog, ai = analog input, a i/o = analog input/output, od = open drain, os = open source, pd = pull down, pu = pull up. nc = no clamp. pad does not clamp input in the absence of power. 2. pins are 5v tolerant, unless indicated.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 17 document #: 249115 revision #: 003 rev. date: 08/07/01 this multi-port repeater provides six (lxt9863) or eight (LXT9883) 10base-t/100base-tx ports. in addition, each device also provides two media independent interface (mii) expansion ports that may be connected to 10/100 macs. the lxt98x3 provides two repeater state machines and two inter-repeater backplanes (irb) on a single chip ? one for 10 mbps and one for 100 mbps operation. the 100 mbps repeater meets ieee 802.3 class ii requirements. the auto-negotiation capability of the lxt98x3 allows it to communicate with connected nodes and configure itself accordingly. the segmented backplane simplifies dual-speed operation, and allows multiple devices to be stacked and function as one logical class ii repeater. up to 240 ports (192 tp ports and 48 mii ports) can be supported in a single stack. 3.2 port configuration the lxt98x3 powers up in auto-negotiation mode for all twisted-pair ports. 3.2.1 auto-negotiation all tp ports on power-up are configured to establish link via auto-negotiation. the port and link partner establish link conditions by exchanging fast link pulse (flp) bursts. each flp burst contains 16 bits of data advertising the port ? s capabilities. if the link partner does not support auto- negotiation, the lxt98x3 determines link state by listening for 100 mbps idle symbols or 10 mbps link pulses. if it detects either of these signals, it configures the port accordingly. figure 3. typical LXT9883 repeater architecture LXT9883 ic device management 10base-t repeater 100base- x repeater led drivers rmon & snmp counters 10 mbps backplane 100 mbps backplane 10/100 phy 10/100 phy mii mii 10/100 phy 10/100 phy 10/100 phy 10/100 phy 10/100 phy 10/100 phy LXT9883 ic device management 10base-t repeater 100base- x repeater led drivers rmon & snmp counters 10 mbps backplane 100 mbps backplane 10/100 phy 10/100 phy mii mii 10/100 phy 10/100 phy 10/100 phy 10/100 phy 10/100 phy 10/100 phy LXT9883 ic 10base-t repeater 100base-x repeater led drivers 10 mbps backplane 100 mbps backplane 10/100 phy 10/100 phy mii mii 10/100 phy 10/100 phy 10/100 phy 10/100 phy 10/100 phy 10/100 phy buffer 100m backplane 100m backplane buffer 10m backplane mii to mii bridge 10m backplane
LXT9883/9863 ? advanced 10/100 unmanaged repeater 18 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 3.2.2 link establishment and port connection once a port establishes link, the lxt98x3 automatically connects it to the appropriate repeater state machine. if link loss is detected and auto-negotiation is enabled, the port returns to the auto- negotiation state. 3.3 interface descriptions the LXT9883 and lxt9863 provide eight and six network interface ports, respectively. each port is a twisted-pair interface that directly supports 100base-tx (100tx) and 10base-t (10t) ethernet applications and fully complies with ieee 802.3 standards. a common termination circuit is used. 3.3.1 twisted-pair interface the lxt98x3 pinout is optimized for dual-height rj-45 connectors. the twisted-pair interface for each port consists of two differential signal pairs ? one for transmit and one for receive. the transmit signal pair is tpop/tpon, the receive signal pair is tpip/tpin. the transmitter requires magnetics with 1:1 turns ratio. the center tap of the primary side of the transmit winding must be tied to a quiet vcc for proper operation. the receiver requires magnetics with a 1:1 turns ratio, and a load of 100 ? . when the twisted-pair port is enabled, the receiver actively biases its inputs to approximately 2.8v. a 4 k ? load is always present across the tpip/tpin pair. when used in 100tx applications, the lxt98x3 sends and receives a continuous, scrambled 125 mbps mlt-3 waveform on this interface. in the absence of data, idle symbols are sent and received in order to maintain the link. when used in 10t applications, the lxt98x3 sends and receives a non-continuous, 10 mbps manchester-encoded waveform. to maintain link during idle periods, the lxt98x3 sends link pulses every 16 ms, and expects to receive them every 10 to 20 ms. each 10t port automatically detects and sends link pulses, and disables its transmitter if link pulses are not detected. each 10base-t port can detect and automatically correct for polarity reversal on the tpip/n inputs. the 10base-t interface provides integrated filters using intel ? s patented filter technology. these filters facilitate low-cost stack designs to meet emi requirements. 3.3.2 media independent interface the lxt98x3 has two identical mii interfaces. the mii has been designed to allow expansion to a media access controller (mac) as shown in figure 4 . this interface is not mdio/mdc capable. these mii ports can be set via hardware tie ups/downs to be either 10 mbps or 100 mbps. these ports are not the full mii drive strength and are intended only for point-to-point links.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 19 document #: 249115 revision #: 003 rev. date: 08/07/01 3.4 repeater operation the lxt98x3 contains two internal repeater state machines ? one operating at 10 mbps and the other at 100 mbps. the lxt98x3 automatically switches each port to the correct repeater, once the operational state of that port has been determined. each repeater connects all ports configured to the same speed (including the mii), and the corresponding inter-repeater backplane. both repeaters perform the standard jabber and partition functions. 3.4.1 100 mbps repeater operation the lxt98x3 contains a complete 100 mbps repeater state machine (100rsm) that is fully ieee 802.3 class ii compliant. any port configured for 100 mbps operation is automatically connected to the 100 mbps repeater. this includes any of the eight media and two mii ports configured for 100 mbps operation. the 100 mbps rsm has its own inter-repeater backplane (100irb). multiple lxt98x3s can be cascaded on the 100irb and operate as one repeater segment. data from any port is forwarded to all other ports in the cascade. the 100irb is a 5-bit symbol-mode interface. it is designed to be stackable. the lxt98x3 performs the following 100 mbps repeater functions: signal amplification, wave-shape restoration, and data-frame forwarding. sop, soj, eop, eoj delay < 46bt; class ii compliant. collision enforcement. during a 100 mbps collision, the lxt98x3 drives a 0101 jam signal (encoded as data 5 on tx links) to all ports until the collision ends. there is no minimum enforcement time. partition. the lxt98x3 partitions any port that participates in excess of 60 consecutive collisions or one long collision approximately 575.2 s long. once partitioned, the lxt98x3 monitors and transmits to the port, but does not repeat data received from the port until it un- partitions. figure 4. mii interface mac txd(3:0) txen txer txclk rxclk lxt98x3 rxd(3:0) rx_dv rx_er crs col
LXT9883/9863 ? advanced 10/100 unmanaged repeater 20 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 un-partition. the un-partition algorithm, which complies with ieee specification 802.3aa, un- partitions a port on either transmit or receive of at least 450-560 bits without collision. isolate. the lxt98x3 isolates any port receiving more than two successive false carrier events. a false carrier event is a packet that does not start with a /j/k symbol pair. un-isolate. the lxt98x3 un-isolates a port that remains in the idle state for 33000 +/- 25% bt or that receives a valid frame at least 450-500 bt in length. jabber. the lxt98x3 ignores any receiver remaining active for more than 57,500 bit times. the lxt98x3 exits this state when either one of the following conditions is met: ? on power-up reset ? when carrier is no longer detected 3.4.2 10 mbps repeater operation the lxt98x3 contains a complete 10 mbps repeater state machine (10rsm) that is fully ieee 802.3 compliant. any port configured for 10 mbps operation is automatically connected to the 10 mbps repeater. this includes any of the media and mii ports configured for 10 mbps operation. the 10rsm has its own inter-repeater backplane (10irb). multiple lxt98x3s can be cascaded on the 10irb and operate as one repeater segment. data from any port is forwarded to all other ports in the cascade. the lxt98x3 performs the following 10 mbps repeater functions: signal amplification, wave-shape restoration, and data-frame forwarding. preamble regeneration. all outgoing packets have a minimum 56-bit preamble and 8-bit sfd. sop, soj, eop, eoj delays meet ieee 802.3 section 9.5.5 and 9.5.6 requirements. collision enforcement. during a 10 mbps collision, the lxt98x3 drives a jam signal ( ? 1010 ? ) to all ports for a minimum of 96 bit times until the collision ends. partition. the lxt98x3 partitions any port in excess of 31 consecutive collisions. once partitioned, the lxt98x3 continues monitoring and transmitting to the port, but does not repeat data received from the port until it properly un-partitions. (also partitions for excessive collision length.) un-partition. the algorithm, which complies with the ieee 802.3 specification, un-partitions a port when data can be either received or transmitted from the port for 450-560 bit times without a collision on that port. jabber. the lxt98x3 asserts a minimum-ifg idle period when a port transmits for longer than 40,000 to 75,000 bit times. 3.5 requirements 3.5.1 power the lxt98x3 has four types of +3.3v power supply input pins: two digital (vcc, gnd) and two analog (vccr, vcct). these inputs may be supplied from a single source. ferrite beads should be used to separate the analog and digital planes. these supplies should be clean.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 21 document #: 249115 revision #: 003 rev. date: 08/07/01 each supply input should be decoupled to ground. refer to table 6 on page 15 for power and ground pin assignments, and to the "general design guidelines ? on page 32. . 3.5.2 clock a stable, external 25mhz reference clock source (ttl) is required to the clk25 pin. the reference clock is used to generate transmit signals and recover receive signals. a crystal-based clock is recommended over a derived clock (i.e., pll-based) to minimize transmit jitter. refer to table 18 on page 37 for a list of recommended oscillators and to table 21 on page 44 for clock timing requirements. 3.5.3 bias resistor the rbias input requires a 22.1 k ? , 1% resistor connected to ground. 3.5.4 reset at power-up, the reset input must be held low until vcc reaches at least 3.15v. a buffer should be used to drive reset if there are multiple lxt98x3 devices. the clock must be active. 3.5.5 irb bus pull-ups even when the lxt98x3 is used in a stand-alone configuration, pull-up resistors are required on the irb signals. see figure 16 and figure 17 on page 43 . 3.6 led operation the lxt98x3 drives the most commonly used leds directly (see "direct drive leds ? on page 24. ). the less frequently used leds are optionally driven via a serial bus to inexpensive serial-to-parallel devices (see ? serial leds ? on this page). 3.6.1 leds at start-up for approximately 2 seconds after the lxt98x3 is reset, all leds are driven to the on state. this start-up routine is an led check. 100 mbps irb 10 mbps irb ir100cfs ir10dat ir100cfsbp ir10ena ir100dv ir10col ir100clk ir10cfs ir10colbp ir10cfsbp
LXT9883/9863 ? advanced 10/100 unmanaged repeater 22 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 3.6.2 led event stretching short lived led status events are stretched so they may be observed by the human eye. refer to the led1, 2, 3 modes section for stretching specifics. 3.6.3 serial led interface the lxt98x3 provides a serial interface to drive additional leds via external 8-bit serial-to- parallel converters. a maximum of 30 leds can be driven, using four s/p devices. collision10/ 100, activity10/100 status indications are output on multiplexed configuration pins and are duplicated on the serial port (see "led pins multiplexed with configuration inputs ? on page 39. ). 3.6.4 serial shifting figure 5 shows the serial led shift loading. figure 5. serial led shift loading 74x164 74x164 74x164 74x164 2 lxt98x3 mii misc act10 act100 3 14 8 57 6 mii 1, 2, 3 misc activity 10m activity 100m shift order mii1 led1 collision 10m actg8 actg8 8 mii1 led2 collision 100m actg7 actg7 7 mii1 led3 not used actg6 actg6 6 mii2 led1 activity 10m actg5 actg5 5 mii2 led2 activity 100m actg4 actg4 4 mi2 led3 global fault actg3 actg3 3 not used not used actg2 actg2 2 not used rps fault actg1 actg1 1 30 leds
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 23 document #: 249115 revision #: 003 rev. date: 08/07/01 3.6.4.1 serial led signals the led serial interface bus consists of three lxt98x3 outputs: clock (ledclk), parallel load clock (ledlat), and output data (leddat). refer to table 5 on page 14 for signal descriptions and to figure 14 on page 40 for an illustration of the led serial interface circuit. refer to figure 6 and table 8 for details on the led serial bit stream. 3.6.4.2 activity graph leds the actgled10 and actgled100 leds are for activity bar graphing. the activity information is integrated and updated over a period of 328.125ms, which has the effect of smoothing out the activity. leds are provided for both the 10 mbps and 100 mbps segments. figure 6. serial led port signaling table 8. serial led port bit stream bit mii ports-led1, 2, 3 misc. actgled10 actgled100 7 mii port 1 - led1 collision - 10m 1 actg8 actg8 6 mii port 1 - led2 collision - 100m 1 actg7 actg7 5 mii port 1 - led3 not used actg6 actg6 4 mii port 2 - led1 activity - 10m 1 actg5 actg5 3 mii port 2 - led2 activity - 100m 1 actg4 actg4 2 mii port 2 - led3 global fault actg3 actg3 1 not used not used actg2 actg2 0 not used rps fault actg1 actg1 1. these leds are multiplexed with configuration inputs. leddat mii ports-led1,2,3 misc. leds actgled10 actgled100 time ledlat leddat ledlat b0 b1 b2 b3 b4 b5 b6 b7 ledclk qa ? -qh ? ( ? 595) qa-qh ( ? 164) b0, b7-b1 b1, b0, b7-b2 b2-b0, b7-b3 b3-b0, b7-b4 b4-b0, b7-b5 b5-b0, b7-b6 b6-b0, b7 b7-b0 b7-b0 qa-qh ( ? 595) b7-b0 b7-b0 leddat ledlat ledclk 122 s 100 ns / 10 mhz
LXT9883/9863 ? advanced 10/100 unmanaged repeater 24 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 there are two display modes for the activity bar graphs, base-2 and base-10. the modes are selected via the ledabgsel pin. refer to table 9 for details. each step led on the bar graph is lit when the percent activity value associated with that step is met or exceeded. 3.6.5 direct drive leds the lxt98x3 provides three direct drive leds for each port (port n _led1:3), excluding the two mii ports. four additional segment leds indicate collision 10/100 and activity 10/100.) the per- port leds are updated simultaneously to illustrate clear, non-overlapping status. the following device pins are multifunctional (input = configuration; output = led driver): col10_led (185), act10_led (183), act100_led (184), and, port8_led2 (175). the drive level is determined by the particular input configuration function of the respective pin. collision and activity indications for both 10m and 100m segments are available in both serial and direct drive. 3.6.6 led modes the four available led modes are described in table 11 - table 15 . hardware pins provide global led mode control. refer to table 5 on page 14 for pin assignments and signal description. table 10 defines terms used to describe led operation. table 9. actgled display modes led ledabgsel = 0 (base-10) ledabgsel = 1 (base-2) actg 8 60+% activity 80+% activity actg 7 50% activity 64% activity actg 6 40% activity 32% activity actg 5 30% activity 16% activity actg 4 20% activity 8% activity actg 3 10% activity 4% activity actg 2 5% activity 2% activity actg 1 1% activity 1% activity table 10. led terms term definition port_enabled true if port is enabled. link_ok true if link is enabled and link is detected. always true for mii port. port_partitioned true if port has been auto partitioned (10mb mode). true if port has been auto partitioned or isolated (100mb mode). port_is_tp true if port is a twisted-pair port. rps_present true if redundant power supply is switched in. rps_fault true if redundant power supply has a fault. rcv_activity true if twisted-pair port on this device is receiving a packet.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 25 document #: 249115 revision #: 003 rev. date: 08/07/01 3.6.6.1 led mode 1 mode 1 operations are described in table 11 . 3.6.6.2 led mode 2 mode 2 operations are described in table 12 . table 11. led mode 1 indications led operating mode hardware control 1 on blink off port n led1 10 mbps operation link_ok, not port_partitioned n/a any other state 100 mbps operation port n led2 10 mbps operation link_ok, port_partitioned 100 mbps operation port n led3 autoblink active 100m link_ok not link_ok (fast blink) 10m link_ok autoblink inactive n/a collision and activity leds any the collision and activity leds are on a per segment basis. pulse stretchers are used to extend the on-time for the leds. for every on- cycle of the stretched leds, an off-cycle, with the same period as the on-cycle, always follows. the collision leds turn on for approximately 120 s when the lxt98x3 detects a collision on the segments. during the time that the led is on, any additional collisions are ignored by the collision led logic. the activity leds turn on for approximately 4 ms when the lxt98x3 detects any activity on the segments. during the time that the led is on any additional activity is ignored by the activity led logic. on blink off global fault any any port_partitioned or rps_fault and rps_present n/a any other state rps fault any rps_present, rps_fault 1. refer to table 11 : led terms, which defines all key terms used in this section.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 26 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 3.6.6.3 led mode 3 mode 3 operations are described in table 13 . table 12. led mode 2 indications led operating mode hardware control 1 on blink off port n led1 any 10m: port_enabled, link_ok, not port_partitioned 100m: port_enabled, link_ok, not port_partitioned 10m: port_enabled, link_ok, and port_partitioned (slow blink) 100m: port_enabled, port_partitioned (slow blink) any other state port n led2 rcv_activity (20 ms pulse) 2 n/a any other state port n led3 autoblink active 100m link_ok no link_ok (fast blink) 10m link_ok autoblink inactive n/a collision and activity leds any the collision and activity leds are on a per segment basis. pulse stretchers are used to extend the on-time for the leds. for every on- cycle of the stretched leds, an off-cycle, with the same period as the on- cycle, always follows. the collision leds turn on for approximately 120 s when the lxt98x3 detects a collision on the segments. during the time that the led is on, any additional collisions are ignored by the collision led logic. the activity leds turn on for approximately 4 ms when the lxt98x3 detects any activity on the segments. during the time that the led is on, any additional activity is ignored by the activity led logic. rps fault any prs_present, no rps_fault prs_present, rps_fault (slow blink) not rps_present global fault any n/a any port_partitioned, any port isolated or rps_fault and rps_present (slow blink) any other state 1. refer to table 10 : led terms, which defines all key terms used in this section. 2. receive activity is stretched to a 20 ms wide pulse. for every on-cycle of the stretched leds, an off-cycle, with the same period as the on-cycle, always follows.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 27 document #: 249115 revision #: 003 rev. date: 08/07/01 table 13. led mode 3 indications led operating mode hardware control on blink off port n led1 10 mbps operation link_ok, not port_partitioned n/a any other state 100 mbps operation port n led2 any rcv_activity (20 ms pulse) 2 n/a any other state port n led3 autoblink active 100m link_ok no link_ok (fast blink) 10m link_ok autoblink inactive 100m mode selected n/a 10m mode selected collision and activity leds any the collision and activity leds are on a per segment basis. pulse stretchers are used to extend the on-time for the leds. for every on- cycle of the stretched leds, an off-cycle, with the same period as the on- cycle, always follows. the collision leds turn on for approximately 120 s when the lxt98x3 detects a collision on the segments. during the time that the led is on, any additional collisions is ignored by the collision led logic. the activity leds turn on for approximately 4 ms when the lxt98x3 detects any activity on the segments. during the time that the led is on, any additional activity is ignored by the activity led logic. global fault any any port_partitioned or rps_fault and rps_present n/a any other state rps fault any rps_present, rps_fault 1. refer to table 10 : led terms, which defines all key terms used in this section. 2. receive activity is stretched to a 20 ms wide pulse. for every on-cycle of the stretched leds, an off-cycle, with the same period as the on-cycle, always follows.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 28 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 3.6.6.4 led mode 4 mode 4 operations are described in table 14 . 3.7 irb operation the inter-repeater backplane (irb) allows multiple devices to operate as a single logical repeater, exchanging data and collision status information. each segment on the lxt98x3 has its own complete, independent irb. the backplanes use a combination of digital and analog signals as shown in figure 8 on page 30 . 3.7.1 irb signal types irb signals can be characterized by the following connection types (for stacking and cascading connections, see table 15 on page 30 ): local ? connected between devices on the same board stack ? connected between boards full ? connected between devices in the same board and between boards. table 14. led mode 4 indications led operating mode hardware control 1 on blink off port n led1 10 mbps operation link_ok, not port_partitioned 20 ms blink indicates rcv_activity 2 any other state 100 mbps operation any other state port n led2 10 mbps operation link_ok, port_partitioned n/a any other state 100 mbps operation port n led3 autoblink active 100m link_ok no link_ok (fast blink)) 10m link_ok autoblink inactive n/a collision and activity leds any the collision and activity leds are on a per segment basis. pulse stretchers are used to extend the on-time for the leds. for every on-cycle of the stretched leds, an off-cycle, with the same period as the on-cycle, always follows. the collision leds turn on for approximately 120 s when the lxt98x3 detects a collision on the segments. during the time that the led is on, any additional collisions are ignored by the collision led logic. the activity leds turns on for approximately 4 ms when the lxt98x3 detects any activity on the segments. during the time that the led is on, any additional activity is ignored by the activity led logic. global fault any any port partitioned or rps_fault and rps_ present n/a any other state rps fault any rps_fault and rps_ present 1. refer to table 10 : led terms, which defines all key terms used in this section. 2. receive activity is stretched to a 20 ms wide pulse. for every on-cycle of the stretched leds, an off-cycle, with the same period as the on-cycle, always follows.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 29 document #: 249115 revision #: 003 rev. date: 08/07/01 3.7.2 10m-only operation 3.7.2.1 mac irb access the macactive pin allows an external mac or other digital asic to interface directly to the 10 mbps irb. when the macactive pin is asserted, the lxt98x3 drives the ir10cfs and ir10cfsbp signals on behalf of the external device, allowing it to participate in collision detection functions. 3.7.3 lxt98x/91x/98xx compatibility the lxt98x3 devices feature low-power 3.3v design. the lxt98x and lxt91x devices operate at 5v and are incompatible with the lxt98x3 devices in cascades. the lxt98x3 devices, however, are backwards stackable with lxt98x and lxt91x repeaters. refer to "inter-repeater backplane compatibility ? on page 41. . figure 7. 100m irb connection ir100dat(4:0) ir100dv ir100clk ir100cfs ir100dat(4:0) ir100dv ir100clk ir100cfsbp hub #1 hub #2 74lvt245 74lvt245 ir100den ir100den ir100sngl ir100col ir100cfs ir100sngl ir100col lxt98x3 lxt98x3 (0) lxt98x3 (0) lxt98x3 cascade stack
LXT9883/9863 ? advanced 10/100 unmanaged repeater 30 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 figure 8. irb block diagram table 15. cascading and stacking connections signal type connections between devices (cascading) connections between boards (stacking) local connect all. do not connect . stack for devices with fps = 0, pull-up at each device and do not interconnect . connect devices with fps = 0 between boards. use one pull-up resistor per stack. full connect all. connect using buffers. digital irb signals include irndat, irncol, ir10colbp, irnena and irnclk. local analog irb signal: irncfs. inter-board analog irb signal: irncfsbp. this diagram shows a single irb. the lxt98x3 actually has two independent irbs, one per speed/segment. ?245 fps = 0 fps = 1 fps = 1 hub board 1 digital irb signals analog irb signals irden holdcol ?245 fps = 0 fps = 1 fps = 1 hub board 2 digital irb signals analog irb signals irden holdcol ?245 fps = 0 fps = 1 fps = 1 hub board n digital irb signals analog irb signals irden holdcol holdcol is used on the 10mbps irb only.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 31 document #: 249115 revision #: 003 rev. date: 08/07/01 3.8 mii port operation the lxt98x3 mii ports allow direct connection with a mac. the mii ports can operate at either 10 mbps or 100 mbps. speed control is provided via mii n_ spd. for 100 mbps operation, set mii n _spd = 1. for 10 mbps operation, set mii n_ spd = 0. 3.8.1 preamble handling when operating at 100 mbps, the lxt98x3 passes the full 56 bits of preamble through before sending the sfd. when operating at 10 mbps, the lxt98x3 sends data across the mii starting with the 8-bit sfd (no preamble bits). table 16. irb signal details name pad type buffer pull-up connection type 100 mbps irb signals ir100dat<4:0> digital yes no full ir100clk digital yes 1k full ir100dv digital, open drain yes 300 ? full ir100cfs analog no 215 ? , 1% local ir100cfsbp analog no 91 ? , 1% stack ir100col digital no no local ir100sngl digital no no local ir100den digital, open drain n/a 1 330 ? local 10 mbps irb signals ir10dat digital, open drain yes 330 ? full ir10clk digital yes no full ir10ena digital, open drain yes 330 ? full ir10cfs analog no 215 ? , 1% local ir10cfsbp analog no 330 ? , 1% stack ir10col digital no 330 ? , 1% local ir10colbp digital no 330 ? , 1% stack ir10den digital, open drain n/a 1 330 ? local 1. driver enable signals are provided to control an external bidirectional transceiver.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 32 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 4.0 application information 4.1 general design guidelines following generally accepted design practices is essential to minimize noise levels on power and ground planes. up to 50mv of noise is considered acceptable. 50mv to 80mv of noise is considered marginal. high-frequency switching noise can be reduced, and its effects can be eliminated, by following these simple guidelines throughout the design: fill in unused areas of the signal planes with solid copper. attach them with vias to a vcc or ground plane that is not located adjacent to the signal layer. use ample bulk and decoupling capacitors throughout the design (a .01 f value is recommended for decoupling caps). provide ample power and ground planes. provide termination on all high-speed switching signals and clock lines. provide impedance matching on long traces to prevent reflections. route high-speed signals next to a continuous, unbroken ground plane. filter and shield dc-dc converters, oscillators, etc. do not route any digital signals between the lxt98x3 and the rj-45 connectors at the edge of the board. do not extend any circuit power and ground plane past the center of the magnetics or to the edge of the board. use this area for chassis ground, or leave it void. figure 9. LXT9883 mii operation mii n _txd<3:0> mii n _txen mii n _txer mii n _txclk mii n _rxclk mii n _rxd<3:0> mii n _rxdv mii n _rxer mii n _crs mii n _col LXT9883 10/100 mac port 1 port 2 port 3 port 4 ports 1, 2 tp ports mii ports port 6 port 7 port 8 port 5 the two LXT9883 mii ports act as the phy side of the mii. an external mac sends tx data to the LXT9883 to be repeated to the network. the LXT9883 repeats network data to the mac via the rx data lines.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 33 document #: 249115 revision #: 003 rev. date: 08/07/01 4.2 power and ground 4.2.1 supply filtering power supply ripple and digital switching noise on the vcc plane causes emi and degrades line performance. predicting a design ? s performance is difficult, although certain factors greatly increase the risks: poorly-regulated or over-burdened power supplies. wide data busses (>32-bits) running at a high clock rate. dc-to-dc converters. many of these issues can be improved by following good general design guidelines. in addition, intel recommends filtering between the power supply and the analog vcc pins of the lxt98x3. filtering has two benefits. first, it keeps digital switching noise out of the analog circuitry inside the lxt98x3, which helps line performance. second, if the vcc planes are laid out correctly, it keeps digital switching noise away from external connectors, reducing emi. the vcc plane should be divided into two sections. the digital section supplies power to the digital vcc pins and to the external components. the analog section supplies power to vccr and vcct pins of the lxt98x3. the break between the two planes should run under the device. in designs with more than one lxt98x3, use a single continuous analog vcc plane to supply them all. the digital and analog vcc planes should be joined at one or more points by ferrite beads. the beads should produce at least a 100 ? impedance at 100 mhz. the beads should be placed so current flows evenly. the maximum current rating of the beads should be at least 150% of the current that is actually expected to flow through them. each lxt98x3 draws a maximum of 1000 ma from the analog supply so beads rated at 1500 ma should be used. a bulk cap (2.2 -10 f) should be placed on each side of each ferrite bead to ground to stop switching noise from traveling through the ferrite. in addition, a high-frequency bypass cap (.01 f) should be placed near each analog vcc pin to ground. 4.2.2 ground noise the best approach to minimize ground noise is strict use of good general design guidelines and by filtering the vcc plane. 4.2.3 power and ground plane layout considerations the power and ground planes should be laid out carefully. the following guidelines are recommended: follow the guidelines in the application note 113 (lxt98x3 design and layout guide) for locating the split between the digital and analog vcc planes. keep the digital vcc plane away from the tpop/n and tpip/n signals, magnetics, and rj-45 connectors. place the layers so the tpop/n and tpip/n signals are routed near or next to the ground plane. for emi, it is more important to shield tpop/n than tpip/n.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 34 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.4 chassis ground for esd protection, create a separate chassis ground. for isolation, encircle the board and place a ? moat ? around the signal ground plane to separate signal ground from chassis ground. chassis ground should extend from the rj-45 connectors to the magnetics, and can be used to terminate unused signal pairs ( ? bob smith ? termination). in single-point grounding applications, provide a single connection between chassis and circuit grounds with a 2kv isolation capacitor. in multi- point grounding schemes (chassis and circuit grounds joined at multiple points), provide 2kv isolation to the bob smith termination. 4.2.5 the rbias pin the lxt98x3 requires a 22.1 k ?, 1% resistor directly connected between the rbias pin and ground. place the rbias resistor as close to the rbias pin as possible. run an etch directly from the pin to the resistor, sink the other side of the resistor, and surround the rbias trace with a filtered ground. do not run high-speed signals next to rbias .
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 35 document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.6 mii terminations the lxt98x3 miis have high output impedance (250-350 ? ). to minimize reflections, serial termination resistors are recommended on all mii signals, especially with designs with long traces (>3 inches). place the resistor as close to the device as possible. use a software trace termination package to select an optimal resistance value for the specific trace. proper value = nominal trace impedance minus 13 ? . if a software package cannot be used and nominal trace impedance is not known, use 55 ? . figure 10. power and ground connections rbias vcc gnd gnd vcc gnd .01 f 22.1k ? 1% gnd vcc 0.1 f + ferrite beads 10 f +3.3v LXT9883 vcct gnd 10 f .01 f .1 f .1 f digital supply plane analog supply plane .01 f .1 f to output magnetics centertap
LXT9883/9863 ? advanced 10/100 unmanaged repeater 36 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.7 twisted-pair interface the lxt98x3 transmitter uses standard 1:1 magnetics for both receive and transmit. nonetheless, system designers should take precautions to minimize parasitic shunt capacitance and meet return loss specifications. these steps include: place magnetics as close as possible to the lxt98x3. keep transmit pair traces short. do not route transmit pair adjacent to a ground plane. eliminate planes under the transmit traces completely. otherwise, keep planes 3-4 layers away. improve emi performance by filtering the output center tap supply. a single ferrite bead may be used in the center tap supply to all ports. all ports draw a combined total of > 1000 ma, so the bead should be rated at > 1500 ma. place the 270pf 5% capacitors at tpip and tpin to improve the signal-to-noise immunity at the receiver. in addition, follow all the standard guidelines for a twisted-pair interface: route the signal pairs differentially, close together. allow nothing to come between them. keep distances as short as possible; both traces should have the same length. avoid vias and layer changes. keep the transmit and receive pairs apart to avoid cross-talk. to provide maximum isolation, place entire receive termination network on one side and transmit on the other side of the pcb. bypass common-mode noise to ground on the in-board side of the magnetics using 0.01 f capacitors. keep termination circuits grouped closely together and on the same side of the board. always put termination circuits close to the source end of any circuit. 4.2.7.1 magnetics information the lxt98x3 requires a 1:1 ratio for the receive transformers and a 1:1 ratio for the transmit transformers. the transformer isolation voltage should be rated at 2kv to protect the circuitry from static voltages across the connectors and cables. refer to table 17 for magnetics specifications. table 17. lxt98x3 magnetics specifications parameter min nom max units test condition rx turns ratio ? 1 : 1 ?? tx turns ratio ? 1 : 1 ?? insertion loss 0.0 ? 1.1 db 80 mhz primary inductance 350 ?? h transformer isolation ? 2 ? kv differential to common mode rejection -40 ?? db .1 to 60 mhz
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 37 document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.8 clock a stable, external 25mhz reference clock source (ttl) is required to the clk25 pin. the reference clock is used to generate transmit signals and recover receive signals. a crystal-based clock is recommended over a derived clock (i.e., pll-based) to minimize transmit jitter. refer to table 18 for a list of recommended oscillators and to table 21 on page 44 for clock timing requirements. -35 ?? db 60 to 100 mhz return loss - standard -16 ?? db 30 mhz -10 ?? db 80 mhz table 17. lxt98x3 magnetics specifications parameter min nom max units test condition table 18. oscillator manufacturers manufacturer part number frequency cts mxo45 / 45lv 25 mhz epson america sg-636 series 25 mhz
LXT9883/9863 ? advanced 10/100 unmanaged repeater 38 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 figure 11. typical twisted-pair port interface and power supply filtering figure 12. typical reset circuit tpfip tpin rj45 tpop tpon vcct gnd 0.1 f .01 f 50 ? 1% to twisted-pair network 3 6 1 2 1:1 1:1 lxt98x3 50 ? 50 ? 50 ? 50 ? 50 ? 50 ? 4 5 8 7 50 ? 1% 0.01 f 5% 270 pf 5% 270 pf 5% 0.001 f 2kv 0.001 f 2kv 0.001 f 2kv tpip .01 f vcc c r1 r2 ? 1 4 d note: t(cr1 > power supply ramp up time. r2 discharges c when supply goes away. the ? 14 is needed for multiple lxt98x3 devices.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 39 document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.9 led circuits 4.2.9.1 direct drive leds each direct drive led has a corresponding open-drain pin. the leds are connected, via a current limiting resistor, to a positive voltage rail. the leds are turned on when the output pin drives low. the open-drain led pins are 5v tolerant, allowing use of either a 3.3v or 5v rail. a 5v rail eases led component selection by allowing more common, high forward voltage leds to be used. refer to figure 13 for a circuit illustration. 4.2.9.2 led pins multiplexed with configuration inputs some static configuration inputs are multiplexed with led pins to reduce the lxt98x3 pin count. these led pins are configured by current sinking (open- drain output) and sourcing (open-source output). if the led pin sinks the led current, the configuration value is ? 1 ? . if led pin sources the current, the configuration value is a ? 0 ? . the lxt98x3 detects the configuration value following reset and then selects the appropriate output drive circuit (open drain or source). if the led function of a multiplexed configuration pin is not used, tie the pin to ground or vcc via a 100 ? 500k ? resistor to set the configuration value. multiple led configuration pins can be tied off with a single resistor to set them all to the same value. refer to figure 13 for a circuit illustration. for configuration values of ? 1 ? , a 3.3v or a 5v rail can be used to drive the leds (to ease led selection as with direct drive leds). for configuration values of ? 0 ? , external buffering is used when 5v led driving is desired. (this buffering could be as simple as a single transistor.) as an alternative, use the copies of the multiplexed led data found on the led serial interface. 5v led driving is achieved. also, if a 5v tolerant serial-to-parallel device is used for the led serial interface, 5v led driving is achieved (see "serial leds ? on page 40. ). figure 13. led circuits - direct drive & multiplexed configuration inputs inside ic outside ic direct drive r v led inside ic outside ic configuration = ? 1 ? inside ic outside ic configuration = ? 0 ? r v led r v led = 3.3 to 5 volts +/- 5% multiplexed multiplexed v cc = 3.3 volts +/- 5% inside ic outside ic configuration = ? 0 ? v cc multiplexed with transistor buffer r v led 100k ? rb v cc
LXT9883/9863 ? advanced 10/100 unmanaged repeater 40 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 4.2.9.3 serial leds the lxt98x3 provides a serial interface to support additional led options. standard shift registers, either 74x595s (8-bit serial-to-parallel with output registers) or 74x164s (8-bit s/p without registers) can be used to drive these additional leds. collision10/100 and activity10/100 status indications are provided on multiplexed configuration pins and duplicated on the serial port. the led serial interface consists of three outputs: clock (ledclk), parallel latch clock (ledlat), and output data (leddat). the parallel latch clock is used only with the 74x595 implementation. refer to figure 14 for an illustration of the led serial interface circuit. potentially, 30 leds can be driven by the led serial interface via 4 s/p devices. the s/p serial output is connected to the serial input of the first serial input device. to expand the chain, connect the last serial output to serial input of next serial interface device. serial led data is output in the anticipated priority order, from least likely to most likely to be used: unused ? 595/ ? 164 parallel outputs mii ports - led1, 2, 3 miscellaneous leds (repeat of collision10/100, repeat of activity10/100, global fault, rps fault) actgled10 actgled100 this allows the user to leave off devices in the serial-to-parallel chain if the leds associated with that condition aren ? t desired. refer to figure 6 on page 23 which illustrates the led serial interface port signalling and table 8 on page 23 which documents the serial led stream. . figure 14. serial led circuit ser rclk srclk qa qb . . . qh qh ? led cct. led cct. led cct. r v led led cct. v led side . . . v led = 3.3 to 5 volts +/- 5% 74x595 . . . led cct. led cct. led cct. . . . up to 2 more ? 595s/8xleds leddat ledlat ledclk . . . up to 2 more ? 164s/8xleds led cct. led cct. led cct. v led . . . led cct. led cct. led cct. . . . leddat ledclk qa qb . . . qh a b clk 74x164 qa qb . . . qh a b clk 74x164 actgled100 actgled10 actgled100 actgled10 ser rclk srclk qa qb . . . qh qh ? 74x595 lxt98x3 lxt98x3
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 41 document #: 249115 revision #: 003 rev. date: 08/07/01 4.3 inter-repeater backplane compatibility the inter-repeater backplane (irb) comprises two parts: local ? the backplane between cascaded devices on the same board. stack ? the backplane between multiple boards. each of these backplanes consists of both analog and digital signals. 4.3.1 local backplane ? 3.3v only the lxt98x3 local backplane operates at 3.3v only. lxt98x and lxt91x devices operate at 5v. lxt98x3 devices are, therefore, not cascadable with lxt98x and lxt91x devices. note: do not mix lxt98x3 with either lxt98x or lxt91x devices on the local backplanes. 4.3.2 stack backplane ? 3.3v or 5v the lxt98x3 stack backplanes can be configured to be either 3.3v or 5v. comp_sel (pin 39), a special input pin, selects between the two voltage modes, depending on whether 3.3v or 5v is applied. 4.3.2.1 3.3v-only stacks apply 3.3v to comp_sel, ir100cfsbp , ir10cfsbp , and ir10colbp for lxt98x3 backplane operation 4.3.2.2 for 5v backwards stackability apply 5v to comp_sel, ir100cfsbp , ir10cfsbp , and ir10colbp for lxt98x and lxt91x backplane operation. note: with either mode (3.3v or 5v), comp_sel draws less than 3 ma. 1. the external pull-up resistor values remain the same, regardless of 3.3v or 5v backplane operation. 2. the recommended digital signal external buffer has been changed to 74lvt245 for the lxt98x3. 4.3.2.3 3.3v and 5.0v stacking boards cannot be mixed 4.3.2.3.1 3.3v operation boards designed for 3.3v backplane operation should only be stacked with other 3.3v boards. existing lxt98x or lxt91x based designs cannot operate in 3.3v. 4.3.2.3.2 incompatible stacking configurations the following stacking configurations are incompatible:
LXT9883/9863 ? advanced 10/100 unmanaged repeater 42 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 a lxt98x3-based board configured for 3.3v backplane operation and lxt98x or lxt91x based boards (5v only). a lxt98x3-based board configured for 3.3v backplane operation and a lxt98x3-based board configured for 5v backplane operation. note: stacking boards designed for 3.3v backplane operation with boards designed for 5v backplane operation causes network errors. 4.3.2.3.3 5v operation boards designed for 5v backplane operation should only be stacked with other 5v boards: lxt98x or lxt91x-based designs. lxt98x3 designs configured for 5v backplane operation. the configuration input must be connected to 5v for compatibility with lxt98x or lxt91x-based designs. the 5v can be supplied from the stacking cable, or a 5v source must exist within the board itself. caution: stacking boards designed for 5v backplane operation with boards designed for 3.3v backplane operation causes network errors. figure 15. 100m backplane connection between lxt98x and lxt98x3 ir100dat(4:0) ir100dv ir100clk ir100cfs ir100dat(4:0) ir100dv ir100clk ir100cfsbp hub #1 hub #2 98x3 buffer buffer ir100den ir100den ir100sngl ir100col ir100cfs ir100sngl ir100col (000) (00) 98x3 98x 1. the lxt98x and LXT9883 devices can share the same inter-repeater backplane so long as the proper backplane buffers are used. configuration is set to 5v. 2. for lxt98x, lxt91x: the buffer should be the 74abt245. for LXT9883: in the 5v tolerant backplane, the buffer can be either 74abt245 or 74lvt245 3. layout follows the same pattern for 10m operation. 98x 5v 5v
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 43 document #: 249115 revision #: 003 rev. date: 08/07/01 figure 16. typical 100 mbps irb implementation figure 17. typical 10 mbps irb implementation lxt98x3 fps = 1 lxt98x3 fps = 1 215 ? 1% 300 ? ir100dv\ ir100dat <4:0> ir100cfs\ ir100col\ ir100sngl ? 245 ir100datbp ir100dvbp\ dir ena ir100clkbp ab lxt98x3 fps = 0 ir100cfsbp\ ir100den\ isolate 91 ? 1%* +3.3v 330 ? ir100clk ir100den\ ir100dv\ ir100dat stack or segment connector ir100cf sbp\ +3.3v 91 ? 91 ? 2 1 1 ? comp_sel +3.3v +3.3v ir100cf sbp\ 1. in stacked configurations, all devices with fps/ = 0 are tied together at ir100cfsbp. the entire stack must be pulled up by only one resistor per signal. pull-up resistor is installed on one board only. (board selection is application specific.) 2. all devices with fps 0 require individual pull-up resistors at ir100cfsbp. 3. pull-up voltage should be the same as comp_sel. LXT9883 fps 1 LXT9883 fps 1 +3.3v 215 ? 1% 330 ? ir10ena\ ir10dat ir10cfs\ ir10col\ holdcol ir10clk ? 245 ir10datbp ir10enabp\ dir ena ir10clkbp ab LXT9883 fps 0 ir10colbp\ ir10cfsbp\ ir10den\ 330 ? 1% 330 ? 1% +3.3v 330 ? ir10den\ ir10clk ir10ena\ ir10dat ir10colbp\ ir10cfsbp\ ir10colbp\ ir10cfsbp\ +3.3v 330 ? 330 ? 330 ? 330 ? stack or segment connector 2 1 comp_sel 1. in stacked configurations, all devices with fps/ = 0 are tied together at ir100cfsbp. the entire stack must be pulled up by only one resistor per signal. pull-up resistor is installed on one board only. (board selection is application specific.) 2. all devices with fps 0 require individual pull-up resistors at ir100cfsbp. 3. pull-up voltage should be the same as comp_sel.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 44 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 5.0 test specifications note: table 19 through table 34 and figure 18 through figure 25 represent the target specifications of the lxt98x3 and are subject to change. final values will be guaranteed by test except, where noted, by design. the minimum and maximum values listed in table 21 through table 34 will be guaranteed over the recommended operating conditions specified in table 20 . table 19. absolute maximum ratings parameter symbol min max units supply voltage v cc -0.3 4.0 v storage temperature t st -65 +150 o c caution: exceeding these values may cause permanent damage. functional operation under these conditions is not implied. exposure to maximum rating conditions for extended periods may affect device reliability. table 20. operating conditions parameter sym min typ 1 max units recommended supply voltage v cc 3.15 3.3 3.45 v v ccr 3.15 3.3 3.45 v v cct 3.15 3.3 3.45 v recommended operating temperature ambient t opa 0 ? 70 c case t opc 0 ? 115 c power consumption 8 ports active p c ?? 3.03 w 6 ports active p c ?? 2.50 w 1. typical values are at 25 c and are for design aid only; they are not guaranteed and not subject to production testing. table 21. input system clock 1 requirements parameter 2 symbol min typ 3 max units test conditions frequency ?? 25 ? mhz ? frequency tolerance ??? 100 ppm ? duty cycle ? 40 ? 60 % ? 1. the system clock is clk25 (pin 54). 2. these requirements apply to the external clock supplied to the lxt98x3, not to lxt98x3 test specifications. 3. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 45 document #: 249115 revision #: 003 rev. date: 08/07/01 table 22. i/o electrical characteristics parameter sym min typ 1 max units test conditions input low voltage v il ?? 0.8 v ttl inputs ?? 30 % v cc cmos inputs 2 ?? 1.0 schmitt triggers 3 input high voltage v ih 2.0 ?? v ttl inputs 70 ?? % v cc cmos inputs 2 v cc - 1.0 ?? v schmitt triggers 3 hysteresis voltage ? 1.0 ?? v schmitt triggers 3 output low voltage v ol ?? 0.4 v i ol = 1.6 ma output low voltage (led) v oll ?? 1.0 v i oll = 10 ma output high voltage v oh 2.2 ?? v i oh = 40 a input low current i il -100 ?? a ? input high current i ih ?? 100 a ? output rise / fall time t rf ? 310ns c l = 15 pf 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. does not apply to irb pins. refer to table 23 and table 24 for irb i/o characteristics. 3. applies to reset, clk25, ir100sngl, ir100col, ir100dv, ir100dat n , ir100clk, and ir10clk pins. table 23. 100 mbps irb electrical characteristics parameter symbol min typ 1 max units test conditions output low voltage v ol ? .3 .7 v r l = 330 ? output rise or fall time t rf ? 410nsc l = 1 5 pf input high voltage v ih v cc - 2.0 ?? v cmos inputs v cc - 1.0 ?? v ir100clk (schmitt trigger) input low voltage v il ?? 2.0 v cmos inputs ?? 1.0 ir100clk (schmitt trigger) hysteresis voltage ? 1.0 ?? v ir100clk (schmitt trigger) 3.3v operation ir100cfs current single drive ?? 6.8 ? ma r l = 215 ? collision ?? 13.5 ? ma r l = 215 ? ir100cfsbp current single drive ?? 16.1 ? ma r l = 91 ? 2 collision ?? 31.8 ? ma r l = 91 ? 2 ir100cfs/bp voltage single drive ?? 1.83 ? v ? collision ?? 0.4 ? v ? 1. typical values are at 25 c and are for design aid only; they are not guaranteed and not subject to production testing. 2. 91 ? resistors provide greater noise immunity. systems using 91 ? resistors are backwards stackable with systems using 100 ? resistors.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 46 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 5.0v operation ir100cfs current single drive ?? n/a ? ma r l = 215 ? collision ?? n/a ? ma r l = 215 ? ir100cfsbp current single drive ?? 24.2 ? ma r l = 91 ? 2 collision ?? 42 ? ma r l = 91 ? 2 ir100cfs/bp voltage single drive ?? 2.8 ? v ? collision ?? 0.6 ? v ? table 24. 10 mbps irb electrical characteristics parameter symbol min typ 1 max units test conditions output low voltage v ol 0.1.4vr l = 330 ? output rise or fall time t rf ? 410nsc l = 15 pf input high voltage v ih v cc - 2.0 ?? v cmos inputs v cc - 2.0 ?? v ir10clk (schmitt trigger) input low voltage v il ?? 2.0 v cmos inputs ?? 1.0 v ir10clk (schmitt trigger) hysteresis voltage ? 0.5 ?? v ir10clk (schmitt trigger) 3.3v operation ir10cfs current single drive ?? 6.8 ? ma r l = 215 ? collision ?? 13.5 ? ma r l = 215 ? ir10cfsbp current single drive ?? 4.5 ? ma r l = 330 ? collision ?? 8.8 ? ma r l = 330 ? ir10cfs/bp voltage single drive ? 1.3 1.83 2.4 v ? collision ? 0.2 0.4 0.6 v ? 5.0v operation ir10cfs current single drive ?? n/a ? ma r l = 215 ? collision ?? n/a ? ma r l = 215 ? ir10cfsbp current single drive ?? 7.0 ? ma r l = 330 ? collision ?? 13.5 ? ma r l = 330 ? ir10cfs/bp voltage single drive ? 1.9 2.8 3.2 v ? collision ? 0.4 0.6 0.8 v ? 1. typical values are at 25 c and are for design aid only; they are not guaranteed and not subject to production testing. table 23. 100 mbps irb electrical characteristics (continued) parameter symbol min typ 1 max units test conditions 1. typical values are at 25 c and are for design aid only; they are not guaranteed and not subject to production testing. 2. 91 ? resistors provide greater noise immunity. systems using 91 ? resistors are backwards stackable with systems using 100 ? resistors.
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 47 document #: 249115 revision #: 003 rev. date: 08/07/01 table 25. 100base-tx transceiver electrical characteristics parameter symbol min typ 1 max units test conditions peak differential output voltage (single ended) v p 0.95 1.0 1.05 v note 2 signal amplitude symmetry ? 98 ? 102 % note 2 signal rise/fall time trf 3.0 ? 5.0 ns note 2 rise/fall time symmetry trfs ?? 0.5 ns note 2 duty cycle distortion ??? +/- 0.5 ns offset from 8 ns pulse width at 50% of pulse peak, overshoot vo ?? 5% ? 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. measured at line side of transformer, line replaced by 100 ? (1%) resistor. table 26. 10base-t transceiver electrical characteristics parameter symbol min typ 1 max units test conditions transmitter peak differential output voltage v p 2.2 2.5 2.8 v measured at line side of transformer, line replaced by 100 ? ( .1%) resistor transmit timing jitter addition 2 ? 8 ? 24 ms 0 line length for internal mau transmit timing jitter added by the mau and pls sections 2, 3 ? 0 ? 11 ns after line model specified by ieee 802.3 for 10base-t internal mau receiver receive input impedance z in ? 20 ? k ? between tpip/tpin differential squelch threshold v ds ? 390 ? mv 5 mhz square wave input, 750 mvpp 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. parameter is guaranteed by design; not subject to production testing. 3. ieee 802.3 specifies maximum jitter additions at 1.5 ns for the aui cable, 0.5 ns from the encoder, and 3.5 ns from the mau.
LXT9883/9863 ? advanced 10/100 unmanaged repeater 48 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 figure 18. 100 mbps tp port-to-port delay timing table 27. 100 mbps tp port-to-port delay timing parameters parameter symbol min typ 1 max units 2 test conditions tpip/n to tpop/n, start of transmission t 1a ?? 46 bt ? tpip/n to tpop/n, end of transmission t 1b ?? 46 bt ? tpip/n collision to tpop/n, start of jam t 1c ?? 46 bt ? tpip/n idle to tpop/n, end of jam t 1d ?? 46 bt ? 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 100base-t = 10 -8 s or 10ns. tp input #2 t 1c p input #1 tp output jam t 1d t 1a tp input tp output t 1b normal propagation collision jamming
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 49 document #: 249115 revision #: 003 rev. date: 08/07/01 figure 19. 100base-tx mii-to-tp port timing table 28. 100base-tx mii-to-tp port timing parameters parameter sym min typ 1 max units 2 test condition txd, tx_en, tx_er setup to tx_clk high t 2a 10 ?? ns ? txd, tx_en, tx_er hold from tx_clk high t 2b 5 ?? ns ? tx_en sampled to crs asserted t 2c 0 ? 4bt ? tx_en sampled to crs de-asserted t 2d 0 ? 16 bt ? tx_en sampled to tpop/n active (tx latency) t 2e ?? 46 bt ? 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 100base-t = 10 -8 s or 10ns. tx_clk txd, tx_en, tx_er crs tpop/n t 2a t 2b t 2c t 2d t 2e
LXT9883/9863 ? advanced 10/100 unmanaged repeater 50 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 figure 20. 100base-tx tp-to-mii timing table 29. 100base-tx tp-to-mii timing parameters parameter sym min typ 1 max units 2 test conditions tpip/n in to crs asserted t 3a ?? 46 bt ? tpip/n quiet to crs de-asserted t 3b ?? 46 bt ? crs asserted to rxd, rx_dv, rx_er t 3c 1 ? 4bt ? crs de-asserted to rxd, rx_dv, rx_er de-asserted t 3d ?? 3bt ? rx_clk falling edge to rxd, rx_dv, rx_er valid t 3e ?? 10 ns ? tpip/n in to col asserted t 3f ?? 46 bt ? tpip/n quiet to col de-asserted t 3g ?? 46 bt ? 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 100base-t = 10 -8 s or 10ns. rx_clk rxd, rx_dv, rx_er crs tpip/n col t 3a t 3b t 3c t 3d t 3f t 3g t 3e
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 51 document #: 249115 revision #: 003 rev. date: 08/07/01 figure 21. 10base-t mii-to-tp timing table 30. 10base-t mii-to-tp timing parameters parameter sym min typ 1 max units 2 test conditions txd, tx_en, tx_er setup to tx_clk high t 10a 10 ?? ns ? txd, tx_en, tx_er hold from tx_clk high t 10b 5 ?? ns ? tx_en sampled to crs asserted t 10c0.92 bt ? 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 10base-t = 10 -7 s or 100ns. tx_clk txd, tx_en, tx_er crs t 10a t 10b t 10c
LXT9883/9863 ? advanced 10/100 unmanaged repeater 52 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 figure 22. 10base-t tp-to-mii port timing table 31. 10base-t tp-to-mii port timing parameters parameter sym min typ 1 max units 2 test conditions tpip/n in to crs asserted t 11a 5 6.6 8 bt ? crs asserted to rxd, rx_dv, rx_er t 11b707684 bt ? rx_clk falling edge to rxd, rx_dv, rx_er valid t 11c ?? 10 ns ? tpip/n in to col asserted t 11d 6 7.4 9 bt ? 1. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 2. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 10base-t = 10 -7 s or 100ns. rx_clk rxd, rx_dv, rx_er crs tpip/n col t 11a t 11b t 11c t 11d
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 53 document #: 249115 revision #: 003 rev. date: 08/07/01 figure 23. 100 mbps tp-to-irb timing table 32. 100 mbps tp-to-irb timing parameters 1 parameter symbol min typ 2 max units 3 test conditions tpip/n to ir100dv low t 12a 18 24 30 bt ? ir100dat to ir100clk setup time. t 12b ? 10 ? ns ? ir100dat to ir100clk hold time. t 12c ? 0 ? ns ? 1. this table contains propagation delays from the tp ports to the irb for normal repeater operation. all values in this table a re output timings. 2. typical figures are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 3. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 100base-t = 10 -8 s or 10ns. tpip/n ir100dv ir100cfs 1r100col ir100dat<4:0> t 12a t 12b ir100clk t 12c
LXT9883/9863 ? advanced 10/100 unmanaged repeater 54 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 figure 24. 10 mbps tp-to-irb timing table 33. 10 mbps tp-to-irb timing parameters 1 parameter 2 symbol min typ 3 max units 4 test conditions tpip/n to ir10ena low t 13a 3 5.1 7 bt ? ir10clk rising edge to ir10dat rising edge. t 13b 25 - 55 ns 330 ? pull-up, 150pf load on ir10dat. 1 k ? pull-up, 150pf load on irclk. ir10clk rising edge to ir10dat falling edge. t 13c 5 - 25 ns 1. this table contains propagation delays from the tp ports to the irb for normal repeater operation. all values in this table a re output timings. 2. there is a delay of approximately 13 to 16 bit times between the assertion of ir10ena and the assertion of ir10clk and ir10dat. this delay does not affect repeater operation because downstream devices begin generating preamble as soon as ir10ena is asserted. 3. typical values are at 25 c and are for design aid only; not guaranteed and not subject to production testing. 4. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 10base-t = 10 -7 s or 100ns. tpip/n ir10ena ir10dat t 13a t 13b ir10clk t 13c
advanced 10/100 unmanaged repeater ? LXT9883/9863 datasheet 55 document #: 249115 revision #: 003 rev. date: 08/07/01 figure 25. 10 mbps irb-to-tp port timing table 34. 10 mbps irb-to tp port timing parameters parameter symbol min typ 1 max units 2 test conditions macactive to ir10ena assertion delay 3 t 14a ? 100 ? ns macactive high to ir10ena low. 4 ir10dat (input) to ir10clk setup time t 14b ? 20 ? ns ir10dat valid to ir10clk rising edge. 4 ir10clk to ir10dat (input) hold time t 14c ? 0 ? ns ir10clk rising edge to ir10dat change. 4 ir10ena asserted to tpop/n active t 14d 5 5.1 6 bt ? 1. typical values are at 25 c and are for design aid only; they are not guaranteed and not subject to production testing. 2. bit time (bt) is the duration of one bit as transferred to/from the mac and is the reciprocal of bit rate. bt for 10base-t = 10 -7 s or 100ns. 3. external devices should allow at least one 10 mhz clock cycle (10 ns) between assertion of macactive and ir10ena. 4. input. macactive ir10ena ir10dat t 14a t 14b ir10clk t 14c tpop/n t 14d
LXT9883/9863 ? advanced 10/100 unmanaged repeater 56 datasheet document #: 249115 revision #: 003 rev. date: 08/07/01 6.0 mechanical specifications figure 26. lxt98x3 package specifications e / 2 a 1 a 2 l a b l 1 3 2 d d 1 e e 1 e dim millimeters min max a - 4.10 a1 0.25 - a2 3.20 3.60 b 0.17 0.27 d 30.30 30.90 d 1 27.70 28.30 e 30.30 30.90 e 1 27.70 28.30 e .50 b asic l 0.50 0.75 l 1 1.30 ref q 0 7 2 5 16 3 5 16 208-pin plastic quad flat package part numbers: LXT9883hc, lxt9863hc commercial temperature range (0 c to 70 c)

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