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1 ? fn6201.1 ISL81387, isl41387 15kv esd protected, dual protocol (rs-232/rs-485) transceivers these devices are bicmos in terface ics that are user configured as either a sing le rs-422/485 differential transceiver, or as a dual (2 tx, 2 rx) rs-232 transceiver. in rs-232 mode, the on-board charge pump generates rs-232 compliant 5v tx output levels, from a supply as low as 4.5v. four small 0.1 f capacitors are required for the charge pump. the transceivers are rs-232 compliant, with the rx inputs handling up to 25v, and the tx outputs handling 12v. in rs-485 mode, the transceive rs support both the rs-485 and rs-422 differential communication standards. the rs-485 receiver features "full failsafe" operation, so the rx output remains in a high state if the inputs are open or shorted together. the rs-485 tr ansmitter supports up to three data rates, two of which are slew rate limited for problem free communications. the charge pump disables in rs-485 mode, thereby saving power, minimizing noise, and eliminating the charge pump capacitors. both rs-232/485 modes feature loopback and shutdown functions. the loopback mode internally connects the tx outputs to the corresponding rx input, which facilitates the implementation of board level self test functions. the outputs remain connected to the loads during loopback, so connection problems (e.g., sh orted connectors or cables) can be detected. the shutdown mode disables the tx and rx outputs, disables the c harge pump if in rs-232 mode, and places the ic in a low current (20 a) mode. the isl41387 is a qfn packaged device that offers additional functionality, including a lower speed and edge rate option (115kbps) for emi sensitive designs, or to allow longer bus lengths. it also features a logic supply voltage pin (v l ) that sets the v oh level of logic outputs, and the switching points of logic inputs, to be compatible with another supply voltag e in mixed voltage systems. the qfn's choice of active high or low rx enable pins increases design flexibility, allowing tx/rx direct ion control via a single signal by connecting den and rxen together. for a dual port version of these devices, please see the isl81334/isl41334 data sheet. features ? user selectable rs-232 or rs-485/422 interface port (two rs-232 transceivers or one rs-485/422 transceiver) ? 15kv (hbm) esd protected bus pins (rs-232 or rs-485) ? flow-through pinouts simplify board layouts ? pb-free plus anneal available (rohs compliant) ? large (2.7v) differential v out for improved noise immunity in rs-485/422 networks ? full failsafe (open/short) rx in rs-485/422 mode ? loopback mode facilitates board self test functions ? user selectable rs-485 data rates . . . . . . . . . . 20mbps - slew rate limited. . . . . . . . . . . . . . . . . . . . . . . 460kbps - slew rate limited (isl41387 only) . . . . . . . . . 115kbps ? fast rs-232 data rate . . . . . . . . . . . . . . . up to 650kbps ? low current shutdown mode. . . . . . . . . . . . . . . . . . .35 a ? qfn package saves board space (isl41387 only) ? logic supply pin (v l ) eases operation in mixed supply systems (isl41387 only) applications ? gaming applications (e.g., slot machines) ? single board computers ? factory automation ? security networks ? industrial/process control networks ? level translators (e.g., rs-232 to rs-422) ? point of sale equipment table 1. summary of features part number no. of ports package options rs-485 data rate (bps) rs-232 data rate (kbps) v l pin? active h or l rx enable? low power shutdown? ISL81387 1 20 ld soic, 20 ld ssop 20m, 460k 650 no h yes isl41387 1 40 ld qfn (6 x 6mm) 20m, 460k, 115k 650 yes both yes data sheet december 20, 2005 caution: these devices are sensitive to electrosta tic discharge; follow proper ic handling procedures. 1-888-intersil or 1-888-468-3774 | intersil (and design) is a registered trademark of intersil americas inc. copyright ? intersil americas inc. 2005. all rights reserved. all other trademarks mentioned are the property of their respective owners.
2 fn6201.1 december 20, 2005 pinouts ISL81387 (soic, ssop) top view isl41387 (qfn) top view ordering information part number (note) part marking temp. range (c) package (pb-free) pkg. dwg. # ISL81387iaz 81387iaz -40 to 85 20 ld ssop m20.209 ISL81387iaz-t 81387iaz -40 to 85 20 ld ssop tape and reel m20.209 ISL81387ibz ISL81387ibz -40 to 85 20 ld soic m20.3 ISL81387ibz-t ISL81387ibz -40 to 85 20 ld soic tape and reel m20.3 isl41387irz 41387irz -40 to 85 40 ld qfn l40.6x6 isl41387irz-t 41387irz -40 to 85 40 ld qfn tape and reel l40.6x6 note: intersil pb-free plus anneal products employ special pb-free material sets; mo lding compounds/die attach materials and 100 % matte tin plate termination finish, which are rohs compliant and compatible with both snpb and pb-free soldering operations. intersil pb-free p roducts are msl classified at pb-free peak reflow temper atures that meet or exceed the pb-free requirements of ipc/jedec j std-020. c1+ c1- v+ a b y z 485/232 den c2+ v cc r a r b d y on v- c2- d z /slew rxen 20 19 18 17 16 15 14 13 12 11 1 2 3 4 5 6 7 8 9 10 gnd 1 40 2 3 4 5 6 7 8 9 10 30 29 28 27 26 25 24 23 22 21 39 38 37 36 35 34 33 32 31 11 12 13 14 15 16 17 18 19 20 nc nc c1- c1+ c2+ c2- nc v cc nc v l r a r b d y d z /slew nc nc nc nc nc on v+ a b y z nc nc nc nc nc den 485/232 gnd gnd rxen nc v- rxen nc spb ISL81387, isl41387
3 fn6201.1 december 20, 2005 table 2. ISL81387 function table inputs receiver outputs driver outputs driver speed (mbps) charge pumps (note 1) loopback (note 2) mode 485/232 on rxen den slew r a r b yz 0 1 0 0 n.a. high-z high-z high-z high-z - on off rs-232 0 1 0 1 n.a. high-z high-z on on 0.46 on off rs-232 0 1 1 0 n.a. on on high-z high-z - on off rs-232 0 1 1 1 n.a. on on on on 0.46 on off rs-232 0 0 0 1 n.a. high-z high-z on high-z 0.46 on off rs-232 0 0 1 0 n.a. high-z on on high-z 0.46 on off rs-232 0 0 1 1 n.a. on on on on 0.46 on on rs-232 x 0 0 0 x high-z high-z high-z high-z - off off shutdown 1 1 0 0 x high-z high-z high-z high-z - off off rs-485 1 x 0 1 1/0 high-z high-z on on 20/0.46 off off rs-485 1 x 1 0 x on high-z high-z high-z - off off rs-485 1 1 1 1 1/0 on high-z on on 20/0.46 off off rs-485 1 0 1 1 1/0 on high-z on on 20/0.46 off on rs-485 notes: 1. charge pumps are on if in rs-232 mode and on or den or rxen are high. 2. loopback is enabled when on = 0, and den = rxen = 1. ISL81387 truth tables rs-232 transmitting mode inputs (on = 1) outputs 485/232 den d y d z yz 010011 010110 011001 011100 0 0 x x high-z high-z rs-232 receiving mode inputs (on = 1) output 485/232 rxen a b r a r b 010011 010110 011001 011100 0 1 open open 1 1 0 0 x x high-z high-z rs-485 transmitting mode inputs (on = 1) outputs 485/232 den d y slew y z data rate (mbps) 110110 20 111101 20 110010 0.46 111001 0.46 1 0 x x high-z high-z - rs-485 receiving mode inputs (on = 1) output 485/232 rxen b-a r a r b 11 -40mv 1 high-z 11 -200mv 0 high-z 1 1 open or shorted together 1 high-z 1 0 x high-z high-z ISL81387, isl41387
4 fn6201.1 december 20, 2005 table 3. isl41387 function table inputs receiver outputs driver outputs driver data rate (mbps) charge pumps (note 3) mode 485/232 on rxen and/or rxen den slew spb r a r b yz 0 1 1 and 0 0 n.a. n.a. high-z high-z high-z high-z - on rs-232 0 1 1 and 0 1 n.a. n.a. high-z high-z on on 0.46 on rs-232 0 1 0 or 1 0 n.a. n.a. on on high-z high-z - on rs-232 0 1 0 or 1 1 n.a. n.a. on on on on 0.46 on rs-232 0 0 1 and 0 1 n.a. n.a. high-z high-z on high-z 0.46 on rs-232 0 0 0 or 1 0 n.a. n.a. high-z on on high-z 0.46 on rs-232 0 0 0 or 1 1 n.a. n.a. on on on on 0.46 on rs-232 (note 4) x 0 1 and 0 0 x x high-z high-z high-z high-z - off shutdown 1 1 1 and 0 0 x x high-z high-z high-z high-z - off rs-485 1 x 1 and 0 1 0 1/0 high-z high-z on on 0.46/0.115 off rs-485 1 x 1 and 0 1 1 x high-z high-z on on 20 off rs-485 1 x 0 or 1 0 x x on high-z high-z high-z - off rs-485 1 1 0 or 1 1 0 1/0 on high-z on on 0.46/0.115 off rs-485 1 1 0 or 1 1 1 x on high-z on on 20 off rs-485 1 0 0 or 1 1 0 1/0 on high-z on on 0.46/0.115 off rs-485 (note 4) 1 0 0 or 1 1 1 x on high-z on on 20 off rs-485 (note 4) notes: 3. charge pumps are on if in rs-232 mode and on or den or rxen is high, or rxen is low. 4. loopback is enabled when on = 0, and den = 1, and (rxen = 1 or rxen = 0). isl41387 truth tables rs-232 transmitting mode inputs (on=1) outputs 485/232 den d y d z yz 0 10011 0 10110 0 11001 0 11100 0 0 x x high-z high-z rs-232 receiving mode inputs (on=1) output 485/232 rxen and/or a b r a r b 00 or 10011 00 or 10110 00 or 11001 00 or 11100 0 0 or 1 open open 1 1 0 1 and 0 x x high-z high-z rs-485 transmitting mode inputs (on=1) outputs data 485/232 den slew spb d y yzmbps 1 1 0 0 0/1 1/0 0/1 0.115 1 1 0 1 0/1 1/0 0/1 0.460 1 1 1 x 0/1 1/0 0/1 20 1 0 x x x high-z high-z - rs-485 receiving mode inputs (on=1) output 485/232 rxen and/or b-a r a r b 10 or 1 -40mv 1 high-z 10 or 1 -200mv 0 high-z 1 0 or 1 open or shorted together 1 high-z 1 1 and 0 x high-z high-z ISL81387, isl41387
5 fn6201.1 december 20, 2005 pin descriptions pin mode function 485/232 both interface mode select input. high for rs-485 mode and low for rs-232 mode. den both driver output enable. the driver outputs, y and z, are enabled by bringing den high. t hey are high impedance when den is low. gnd both ground connection. nc both no connection. on both in rs-232 mode only, on high enables the char ge pumps. on low, with den and rxen low (and rxen high if qfn), turns off the charge pumps (in rs-232 mode), and in either mode plac es the device in low power shutdown. in both modes, when on is low, and den is high, and rxen is high or rxen is low, loopback is enabled. rxen both receiver output enable. rx is enabled when rxen is high; rx is high impedance when rxen is low and, if using the qfn package, rxen is high. when using the qfn and the active high rx enable function, rxen should be high or floating. rxen both active low receiver output enable. rx is enabled when rxen is low; rx is high impedance when rxen is high and rxen is low. (i.e., to use active low rx enable function, tie rxen to gnd). for single signal tx/rx direction control, connect rxen to den. internally pulled high. (qfn only) v cc both system power supply input (5v). v l both logic-level supply. all ttl/cmos inputs and outputs are powered by this supply. (qfn only) a rs-232 receiver input with 15kv esd protection. a low on a forces r a high; a high on a forces r a low. rs-485 inverting receiver input with 15kv esd protection. b rs-232 receiver input with 15kv esd protection. a low on b forces r b high; a high on b forces r b low. rs-485 noninverting receiver input with 15kv esd protection. d y rs-232 driver input. a low on d y forces output y high. similarly, a high on d y forces output y low. rs-485 driver input. a low on d y forces output y high and output z low. similarly, a high on d y forces output y low and output z high. d z rs-232 driver input. a low on d z forces output z high. similarly, a high on d z forces output z low. slew rs-485 slew rate control. with the slew pin high, the drivers run at the maximum slew rate (20mbps). with the slew pin low, the drivers run at a reduced slew rate (460kbp s). on the qfn version, works in conjunction with spb to select one of three rs-485 data rates. internally pulled high in rs-485 mode. spb rs-485 speed control. works in conjunction with the slew pi n to select the 20mbps, 460kbps or 115kbps rs-485 data rate. internally pulled high. (qfn only) r a rs-232 receiver output. rs-485 receiver output: if b > a by at least -40mv, r a is high; if b < a by -200mv or more, r a is low; r a = high if a and b are unconnected (floating) or shorted together (i.e., full fail-safe). r b rs-232 receiver output. rs-485 not used. output is high impedance, and unaffected by rxen and rxen. y rs-232 driver output with 15kv esd protection. rs-485 inverting driver output with 15kv esd protection. z rs-232 driver output with 15kv esd protection. rs-485 noninverting driver output with 15kv esd protection. c1+ rs-232 external capacitor (voltage doubler) is connected to this lead. not needed in rs-485 mode. c1- rs-232 external capacitor (voltage doubler) is connected to this lead. not needed in rs-485 mode. c2+ rs-232 external capacitor (voltage inverter) is connected to this lead. not needed in rs-485 mode. c2- rs-232 external capacitor (voltage inverter) is connected to this lead. not needed in rs-485 mode. v+ rs-232 internally generated positive rs-232 transmi tter supply (+5.5v). c3 not needed in rs-485 mode. v- rs-232 internally generated negativ e rs-232 transmitter supply (-5.5v). c4 not needed in rs-485 mode. ISL81387, isl41387
6 fn6201.1 december 20, 2005 / typical operating circuit rs-232 mode without loopback rs-485 mode without loopback rs-232 mode with loopback rs-485 mode with loopback 18 v cc y z d y d z 0.1 f + 0.1 f + 0.1 f 15 14 6 7 1 2 3 11 v+ v- c1+ c1- c2+ c2- + 0.1 f 20 19 r a a 4 5k ? r b b 516 5k ? c 1 c 2 + c 3 c 4 rxen 12 gnd +5v + 0.1 f 10 485/232 on 813 v cc v cc den 9 v cc note: pinout for soic and ssop 17 r r d d 18 v cc y z d y slew 0.1 f + 0.1 f + 0.1 f 15 14 6 7 1 2 3 11 v+ v- c1+ c1- c2+ c2- + 0.1 f 20 19 r a a 4 r b b 5 16 c 1 c 2 + c 3 c 4 rxen 12 gnd +5v + 0.1 f 10 485/232 on 813 v cc v cc den 9 v cc note: pinout for soic and ssop 17 d r v cc 18 v cc y z d y d z 0.1 f + 0.1 f + 0.1 f 15 14 6 7 1 2 3 11 v+ v- c1+ c1- c2+ c2- + 0.1 f 20 19 r a r b 16 c 1 c 2 + c 3 c 4 rxen 12 gnd +5v + 0.1 f 10 485/232 on 8 13 v cc den 9 v cc note: pinout for soic and ssop 17 d d 5k ? 5k ? a1 4 b1 5 lb rx r r 18 v cc y z d y slew 0.1 f + 0.1 f + 0.1 f 15 14 6 7 1 2 3 11 v+ v- c1+ c1- c2+ c2- + 0.1 f 20 19 r a r b 16 c 1 c 2 + c 3 c 4 rxen 12 gnd +5v + 0.1 f 10 485/232 on 8 13 v cc den 9 v cc note: pinout for soic and ssop 17 d r v cc lb rx a 4 b 5 ISL81387, isl41387
7 fn6201.1 december 20, 2005 absolute m aximum ratings (t a = 25c) thermal information v cc to ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7v v l (qfn only) . . . . . . . . . . . . . . . . . . . . . . . . . -0.5v to v cc + 0.5v input voltages all except a,b (non-qfn package) . . . . . . -0.5v to (v cc + 0.5v) all except a,b (qfn package). . . . . . . . . . . -0.5v to (v l + 0.5v) input/output voltages a, b (any mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25v to +25v y, z (any mode, note 5) . . . . . . . . . . . . . . . . . . . -12.5v to +12.5v r a , r b (non-qfn package). . . . . . . . . . . . -0.5v to (v cc + 0.5v) r a , r b (qfn package) . . . . . . . . . . . . . . . . -0.5v to (v l + 0.5v) output short circuit duration y, z , r a , r b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . indefinite esd rating . . . . . . . . . . . . . . . . . . . . . . . . . see specification table thermal resistance (typical, note 6) ja (c/w) 20 ld soic package . . . . . . . . . . . . . . . . . . . . . . . . 65 20 ld ssop package . . . . . . . . . . . . . . . . . . . . . . . 60 40 ld qfn package. . . . . . . . . . . . . . . . . . . . . . . . . 32 maximum junction temperature (plastic package) . . . . . . . 150c maximum storage temperature range . . . . . . . . . . -65c to 150c maximum lead temperature (soldering 10s) . . . . . . . . . . . . 300c (soic and ssop - lead tips only) operating conditions temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . -40c to 85c caution: stresses above those listed in ?absolute maximum ratings? may cause permanent damage to the device. this is a stress o nly rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. notes: 5. one output at a time, i out 100ma for 10 mins. 6. qfn ja is measured in free air with the component mounted on a high effe ctive thermal conductivity test board with ?direct attach? fe atures. ja for other packages is measured with the component mounted on a high effective thermal conductivity test board in free air. see te c h b r i e f tb379 and tech brief tb389 for details. electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only), unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 7) parameter symbol test conditions temp (c) min typ max units dc characteristics - rs-485 driver (485/232 = v cc ) driver differential v out (no load) v od1 full - - v cc v driver differential v out (with load) v od2 r = 50 ? (rs-422) (figure 1) full 2.5 3.1 - v r = 27 ? (rs-485) (figure 1) full 2.2 2.7 5 v v od3 r d = 60 ? , r = 375 ? , v cm = -7v to 12v (figure 1) full 2 2.7 5 v change in magnitude of driver differential v out for complementary output states ? v od r = 27 ? or 50 ? (figure 1) full - 0.01 0.2 v driver common-mode v out v oc r = 27 ? or 50 ? (figure 1) (note 11) full - - 3.1 v change in magnitude of driver common-mode v out for complementary output states ? v oc r = 27 ? or 50 ? (figure 1) (note 11) full - 0.01 0.2 v driver short-circuit current, v out = high or low i os -7v (v y or v z ) 12v (note 9) full 35 - 250 ma driver three-state output leakage current (y, z) i oz outputs disabled, v cc = 0v or 5.5v v out = 12v full - - 150 a v out = -7v full -150 - - a dc characteristics - rs-232 driver (485/232 = 0v) driver output voltage swing v o all t outs loaded with 3k ? to ground full 5.0 +6/-7 - v driver output short-circuit current i os v out = 0v full -60 25/-35 60 ma dc characteristics - logic pins (i.e., driver and control input pins) input high voltage v ih1 v l = v cc if qfn full 2 1.6 - v v ih2 v l = 3.3v (qfn only) full 2 1.2 - v v ih3 v l = 2.5v (qfn only) full 1.5 1 - v ISL81387, isl41387
8 fn6201.1 december 20, 2005 input low voltage v il1 v l = v cc if qfn full - 1.4 0.8 v v il2 v l = 3.3v (qfn only) full - 1 0.7 v v il3 v l = 2.5v (qfn only) full - 0.8 0.5 v input current i in1 except slew, rxen (qfn), and spb (qfn) full -2 - 2 a i in2 slew (note 12), rxen (qfn), and spb (qfn) full -25 - 25 a dc characteristics - rs-485 receiver inputs (485/232 = v cc ) receiver differential threshold voltage v th -7v v cm 12v, full failsafe full -0.2 - -0.04 v receiver input hysteresis ? v th v cm = 0v 25 - 35 - mv receiver input current (a, b) i in v cc = 0v or 4.5 to 5.5v v in = 12v full - - 0.8 ma v in = -7v full -0.64 - - ma receiver input resistance r in -7v v cm 12v, v cc = 0 (note 10), or 4.5v v cc 5.5v full 15 - - k ? dc characteristics - rs-232 receiver inputs (485/232 = gnd) receiver input voltage range v in full -25 - 25 v receiver input threshold v il full - 1.4 0.8 v v ih full 2.4 1.9 - v receiver input hysteresis ? v th 25 - 0.5 - v receiver input resistance r in v in = 15v, v cc powered up (note 10) full 3 5 7 k ? dc characteristics - receiver outputs (485 or 232 mode) receiver output high voltage v oh1 i o = -2ma (v l = v cc if qfn) full 3.5 4.6 - v v oh2 i o = -650 a, v l = 3v, qfn only full 2.6 2.9 - v v oh3 i o = -500 a, v l = 2.5v, qfn only full 2 2.4 - v receiver output low voltage v ol i o = 3ma full - 0.1 0.4 v receiver short-circuit current i osr 0v v o v cc full 7 - 85 ma receiver three-state output current i ozr output disabled, 0v v o v cc (or v l for qfn) full - - 10 a power supply characteristics no-load supply current, note 8 i cc232 485/232 = 0v, on = v cc full - 3.7 7 ma i cc485 485/232 = v cc , on = v cc full - 1.6 5 ma shutdown supply current i shdn232 on = den = rxen = 0v (rxen = spb = v cc if qfn) full - 5 30 a i shdn485 on = den = rxen = slew = 0v (rxen = v cc , spb = 0v if qfn) full - 35 60 a esd characteristics bus pins (a, b, y, z) any mode human body model 25 - 15 - kv all other pins human body model 25 - 4 - kv rs-232 driver and receiver switching characteristics (485/232 = 0v, all versions and speeds) driver output transition region slew rate sr r l =3k ?, measured from 3v to -3v or -3v to 3v c l 15pf full - 18 30 v/ s c l 2500pf full 4 12 - v/ s electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only), unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 7) (continued) parameter symbol test conditions temp (c) min typ max units ISL81387, isl41387
9 fn6201.1 december 20, 2005 driver output transition time t r , t f r l =3k ? , c l = 2500pf, 10% - 90% full 0.22 1.2 3.1 s driver propagation delay t dphl r l =3k ?, c l = 1000pf (figure 6) full - 1 2 s t dplh full - 1.2 2 s driver propagation delay skew t dskew t dphl - t dplh (figure 6) full - 240 400 ns driver enable time t den 25 - 800 - ns driver disable time t ddis r l =5k ?, measured at v out = 3v 25 - 500 - ns driver enable time from shutdown t densd v out = 3.0v ( note 13) 25 - 20 - s driver maximum data rate dr d r l =3k ?, c l = 1000pf, one transmitter switching full 460 650 - kbps receiver propagation delay t rphl c l = 15pf (figure 7) full - 50 120 ns t rplh full - 40 120 ns receiver propagation delay skew t rskew t rphl - t rplh (figure 7) full - 10 40 ns receiver maximum data rate dr r c l = 15pf full 0.46 2 - mbps rs-485 driver switching characteristics (fast data rate (20mbps), 485/232 = v cc , slew = v cc , all versions) driver differential input to output delay t dlh , t dhl r diff = 54 ? , c l = 100pf (figure 2) full 15 30 50 ns driver output skew t skew r diff = 54 ? , c l = 100pf (figure 2) full - 0.5 10 ns driver differential rise or fall time t r , t f r diff = 54 ? , c l = 100pf (figure 2) full 3 11 20 ns driver enable to output low t zl c l = 100pf, sw = v cc (figure 3) full - 27 60 ns driver enable to output high t zh c l = 100pf, sw = gnd (figure 3) full - 24 60 ns driver disable from output low t lz c l = 15pf, sw = v cc (figure 3) full - 31 60 ns driver disable from output high t hz c l = 15pf, sw = gnd (figure 3) full - 24 60 ns driver enable from shutdown to output low t zl(shdn) r l = 500 ? , c l = 100pf, sw = v cc (figure 3) (note 13) full - 65 250 ns driver enable from shutdown to output high t zh(shdn) r l = 500 ? , c l = 100pf, sw = gnd (figure 3) (note 13) full - 152 250 ns driver maximum data rate f max r diff = 54 ? , c l = 100pf (figure 2) full - 30 - mbps rs-485 driver switching characteristics (medium data rate (460kbps), 485/232 = v cc , slew = spb (qfn only) = gnd, all versions) driver differential input to output delay t dlh , t dhl r diff = 54 ? , c l = 100pf (figure 2) full 200 490 1000 ns driver output skew t skew r diff = 54 ? , c l = 100pf (figure 2) full - 110 400 ns driver differential rise or fall time t r , t f r diff = 54 ? , c l = 100pf (figure 2) full 300 600 1100 ns driver enable to output low t zl c l = 100pf, sw = v cc (figure 3) full - 30 300 ns driver enable to output high t zh c l = 100pf, sw = gnd (figure 3) full - 128 300 ns driver disable from output low t lz c l = 15pf, sw = v cc (figure 3) full - 31 60 ns driver disable from output high t hz c l = 15pf, sw = gnd (figure 3) full - 24 60 ns driver enable from shutdown to output low t zl(shdn) r l = 500 ? , c l = 100pf, sw = v cc (figure 3) (note 13) full - 65 500 ns driver enable from shutdown to output high t zh(shdn) r l = 500 ? , c l = 100pf, sw = gnd (figure 3) (note 13) full - 255 500 ns driver maximum data rate f max r diff = 54 ? , c l = 100pf (figure 2) full - 2000 - kbps electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only), unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 7) (continued) parameter symbol test conditions temp (c) min typ max units ISL81387, isl41387
10 fn6201.1 december 20, 2005 rs-485 driver switching characteristics (slow data rate (115kbps, qfn only), 485/232 = v cc , slew = 0v, spb = v cc ) driver differential input to output delay t dlh , t dhl r diff = 54 ? , c l = 100pf (figure 2) full 800 1500 2500 ns driver output skew t skew r diff = 54 ? , c l = 100pf (figure 2) full - 350 1250 ns driver differential rise or fall time t r , t f r diff = 54 ? , c l = 100pf (figure 2) full 1000 2000 3100 ns driver enable to output low t zl c l = 100pf, sw = v cc (figure 3) full - 32 600 ns driver enable to output high t zh c l = 100pf, sw = gnd (figure 3) full - 300 600 ns driver disable from output low t lz c l = 15pf, sw = v cc (figure 3) full - 31 60 ns driver disable from output high t hz c l = 15pf, sw = gnd (figure 3) full - 24 60 ns driver enable from shutdown to output low t zl(shdn) r l = 500 ? , c l = 100pf, sw = v cc (figure 3) (note 13) full - 65 800 ns driver enable from shutdown to output high t zh(shdn) r l = 500 ? , c l = 100pf, sw = gnd (figure 3) (note 13) full - 420 800 ns driver maximum data rate f max r diff = 54 ? , c l = 100pf (figure 2) full - 800 - kbps rs-485 receiver switching characteristics (485/232 = v cc , all versions and speeds) receiver input to output delay t plh , t phl (figure 4) full 20 50 90 ns receiver skew | t plh - t phl |t skew (figure 4) full - 0.1 10 ns receiver maximum data rate f max full - 40 - mbps receiver enable/disable characteristics (all modes and versions and speeds) receiver enable to output low t zl c l = 15pf, sw = v cc (figure 5) full - 22 60 ns receiver enable to output high t zh c l = 15pf, sw = gnd (figure 5) full - 23 60 ns receiver disable from output low t lz c l = 15pf, sw = v cc (figure 5) full - 24 60 ns receiver disable from output high t hz c l = 15pf, sw = gnd (figure 5) full - 25 60 ns receiver enable from shutdown to output low t zlshdn c l = 15pf, sw = v cc (figure 5) (note 13) rs-485 mode full - 260 700 ns rs-232 mode 25 - 35 - ns receiver enable from shutdown to output high t zhshdn c l = 15pf, sw = gnd (figure 5) (note 13) rs-485 mode full - 260 700 ns rs-232 mode 25 - 25 - ns notes: 7. all currents into device pins are positive; all currents out of device pins are negative. all voltages are referenced to devi ce ground unless otherwise specified. 8. supply current specification is va lid for loaded drivers when den = 0v. 9. applies to peak current. see ?typical pe rformance curves? for more information. 10. r in defaults to rs-485 mode (>15k ? ) when the device is unpowered (v cc = 0v), regardless of the state of the 485/232 pin. 11. v cc 5.25v. 12. the slew pin has a pull-up resistor that enables only when in rs-485 mode (485/232 = v cc ). 13. on, rxen, and den all simult aneously switched low-to-high. electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only), unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 7) (continued) parameter symbol test conditions temp (c) min typ max units ISL81387, isl41387
11 fn6201.1 december 20, 2005 test circuits and waveforms figure 1. rs-485 driver v od and v oc test circuit figure 2a. test circuit figure 2b. measurement points figure 2. rs-485 driver propagation delay and differential transition times figure 3a. test circuit figure 3b. measurement points figure 3. rs-485 driver enable and disable times d den d y v cc v od v oc r r y z r d v cm + - d den d y v cc signal generator c l = 100pf r diff y z c l = 100pf out (z) 3v 0v t plh 1.5v 1.5v v oh v ol 50% 50% t phl out (y) t phl v oh v ol 50% 50% t plh diff out (z - y) t r +v od -v od 90% 90% t f 10% 10% d y skew = |t plh (y or z) - t phl (z or y)| 0v 0v t dhl t dlh d den dy c l 500 ? y z v cc gnd sw signal generator for shdn tests, switch on and den l- h simultaneously parameter output rxen dy sw c l (pf) t hz y/z x 0/1 gnd 15 t lz y/z x 1/0 v cc 15 t zh y/z x 0/1 gnd 100 t zl y/z x 1/0 v cc 100 t zh(shdn) y/z 0 0/1 gnd 100 t zl(shdn) y/z 0 1/0 v cc 100 out (y, z) 3v 0v 1.5v 1.5v v oh 0v 2.3v v oh - 0.5v t hz out (y, z) v cc v ol 2.3v v ol + 0.5v t lz den output high output low t zl t zh t zh(shdn) t zl(shdn) enabled ISL81387, isl41387
12 fn6201.1 december 20, 2005 figure 4a. test circuit figure 4b. measurement points figure 4. rs-485 receiver propagation delay figure 5a. test circuit figure 5b. measurement points figure 5. rs-485 receiver enable and disable times figure 6a. test circuit figure 6b. measurement points figure 6. rs-232 driver propagation delay figure 7a. test circuit figure 7b. measurement points figure 7. rs-232 receiver propagation delay test circuits and waveforms (continued) signal generator r r a rxen b a 0v 15pf v cc r a +1.5v -1.5v t plh 0v 0v v cc 0v 1.5v 1.5v t phl b 1k ? v cc gnd sw for shdn tests, switch on and rxen l- h simultaneously parameter den b sw t hz x +1.5v gnd t lz x-1.5vv cc t zh x +1.5v gnd t zl x-1.5vv cc t zh(shdn) 0 +1.5v gnd t zl(shdn) 0-1.5vv cc signal generator r r a rxen b a 15pf r a 3v 0v 1.5v 1.5v v oh 0v 1.5v v oh - 0.5v t hz r a v cc v ol 1.5v v ol + 0.5v t lz rxen output high output low t zl t zh t zl(shdn) t zh(shdn) enabled d den d y,z v cc signal generator r l y, z c l out (y,z) 3v 0v t dphl 1.5v 1.5v v o+ v o- 0v 0v t dplh d y,z skew = |t dphl - t dplh | r rxen a, b v cc signal generator r a, r b c l = 15pf r a, r b 3v 0v t rphl 1.7v 1.3v v oh v ol 0.8v 2.4v t rplh a, b skew = |t rphl - t rplh | ISL81387, isl41387
13 fn6201.1 december 20, 2005 detailed description the islx1387 port supports dual protocols: rs-485/422, and rs-232. rs-485 and rs-422 are differential (balanced) data transmission standards for use in high speed (up to 20mbps) networks, or long haul and noisy environments. the differential signalling, coupled with rs-485?s requirement for extended co mmon mode range (cmr) of +12v to -7v make these transceivers extremely tolerant of ground potential differences, as well as voltages induced in the cable by external fields. both of these effects are real concerns when communicating over the rs-485/422 maximum distance of 4000? (1220m). it is important to note that the islx1387 don?t follow the rs-485 convention whereby the inverting i/o is labelled ?b/z?, and the noninverting i/o is ?a/y?. thus, in the application diagrams below the 1387 a/y (b/z) pins connect to the b/z (a/y) pins of the generic rs-485/422 ics. rs-422 is typically a point-to-poi nt (one driver talking to one receiver on a bus), or a point-to-multipoint (multidrop) standard that allows only one driver and up to 10 receivers on each bus. because of the one driver per bus limitation, rs-422 networks use a two bus, full duplex structure for bidirectional communication, and the rx inputs and tx outputs (no tri-state required) connect to different busses, as shown in figure 9. tx and rx enables aren?t required, so connect rxen and den to v cc through a 1k ? resistor. conversely, rs-485 is a true multipoint standard, which allows up to 32 devices (any co mbination of drivers- must be tri-statable - and receivers) on each bus. now bidirectional communication takes place on a single bus, so the rx inputs and tx outputs of a port connect to the same bus lines, as shown in figure 8. a port set to rs-485 /422 mode includes one rx and one tx. rs-232 is a point-to-point, singled ended (signal voltages referenced to gnd) communicat ion protocol targeting fairly short (<150?, 46m) and low data rate (<1mbps) applications. a port contains two transceivers (2 tx and 2 rx) in rs-232 mode. protocol selection is handled via the 485/232 logic pin. . figure 8. typical half duplex rs-485 network figure 9. typical rs-422 network 0.1 f + d r v cc gnd ra rxen * den dy y z +5v r t 0.1 f + d r v cc gnd ro re de di a/y b/z +5v 0.1 f + d v cc gnd ro re de di a/y b/z +5v r r t islx1387 generic 1/2 duplex 485 xcvr generic 1/2 duplex 485 xcvr tx/rx * qfn only, connect rxen to gnd a b 0.1 f + d r v cc gnd ra den dy b a +5v 0.1 f + d r v cc gnd ro di a z +5v 0.1 f + v cc gnd ro re +5v r r t ISL81387 (master) generic 422 rx (slave) generic full duplex 422 xcvr (slave) a b r t y z y b 1k ? rxen ISL81387, isl41387
14 fn6201.1 december 20, 2005 islx1387 advantages these dual protocol ics offer many parametric improvements versus those offered on competing dual protocol devices. some of the major improvements are: 15kv bus pin esd - eases board level requirements; 2.7v diff v out - better noise immunity and/or distance; full failsafe rs-485 rx - eliminates bus biasing; selectable rs-485 data rate - up to 20mbps, or slew rate limited for low emi and fewer termination issues; high rs-232 data rate - >460kbps lower tx and rx skews - wider, consistent bit widths; lower i cc - max i cc is 2-4x lower than competition; flow-thru pinouts - tx, rx bus pins on one side/logic pins on the other, for easy routing to connector/uart; smaller (ssop and qfn) and pb-free packaging. rs-232 mode rx features rs-232 receivers invert and convert rs-232 input levels ( 3v to 25v) to the standard ttl/cmos levels required by a uart, asic, or controller serial port. receivers are designed to operate at faster da ta rates than the drivers, and they feature very low skews (10ns) so the receivers contribute negligibly to bit wi dth distortion. inputs include the standards required 3k ? to 7k ? pulldown resistor, so unused inputs may be left unconnected. rx inputs also have built-in hysteresis to increase noise immunity, and to decrease erroneous triggering due to slowly transitioning input signals. rx outputs are short circuit protected, and are tri-statable via the active high rxen pin, when the ic is shutdown (shdn; see tables 2 and 3, and the ?low power shutdown? section), or via the active low rxen pin available on the qfn package option (see ?isl41387 special features? for more details). tx features rs-232 drivers invert and c onvert the standard ttl/cmos levels from a uart, or controller serial port to rs-232 compliant levels ( 5v minimum). the tx delivers these compliant output levels even at data rates of 650kbps, and with loads of 1000pf. the drivers are designed for low skew (typically 12% of the 500kbps bit width), and are compliant to the rs-232 slew rate spec (4 to 30v/ s) for a wide range of load capacitances. tx inputs float if left unconnected, and may cause i cc increases. for the be st results, connect unused inputs to gnd. tx outputs are short circuit protected, and incorporate a thermal shdn feature to protec t the ic in situations of severe power dissipation. see the rs-485 section for more details. drivers tri-state via the active high den pin, in shdn (see tables 2 and 3, and the ?low power shutdown? section), or when the 5v power supply is off. charge pumps the on-chip charge pumps create the rs-232 transmitter power supplies (typically +6/-7v) from a single supply as low as 4.5v, and are enabled only if the port is configured for rs-232 operation, a nd not in shdn. the efficient design requires only four small 0.1 f capacitors for the voltage doubler and inverter functions. by operating discontinuously (i.e., turning off as soon as v+ and v- pump up to the nominal values), the charge pump contribution to rs-232 mode i cc is reduced significantly. unlike competing devices that require the charge pump in rs-485 mode, disabling the charge pump saves power, and minimizes noise. if the application is a dedicated rs-485 port, then the charge pump capacitors aren?t even required. data rates and cabling drivers operate at data rates up to 650kbps, and are guaranteed for data rates up to 460kbps. the charge pumps and drivers are designed such that one driver can be operated at the rated load, and at 460kbps (see figure 33). figure 33 also shows that dr ivers can easily drive several thousands of picofarads at dat a rates up to 250kbps, while still delivering compliant 5v output levels. receivers operate at data rates up to 2mbps. they are designed for a higher data rate to facilitate faster factory downloading of software into the final product, thereby improving the user?s manufacturing throughput. figures 36 and 37 illustrate driver and receiver waveforms at 250kbps, and 500kbps, respectively. for these graphs, one driver drives the specified capacitive load, and a receiver. rs-232 doesn?t require anything special for cabling; just a single bus wire per transmitter and receiver, and another wire for gnd. so an islx1387 rs-232 port uses a five conductor cable for interconnection. bus terminations are not required, nor allowed, by the rs-232 standard. rs-485 mode rx features rs-485 receivers convert differ ential input signals as small as 200mv, as required by the rs-485 and rs-422 standards, to ttl/cmos output levels. the differential rx provides maximum sensitivity, noise immunity, and common mode rejection. per the rs-485 standard, receiver inputs function with common mode voltages as great as 7v outside the power supplies (i.e., +12v and -7v), making them ideal for long networks where induced voltages are a realistic concern. each rs-485/422 port includes a single receiver (ra), and the unused rx output (rb) is disabled. worst case receiver input currents are 20% lower than the 1 ?unit load? (1ma) rs-485 limit, which translates to a 15k ? minimum input resistance. ISL81387, isl41387
15 fn6201.1 december 20, 2005 these receivers include a ?fu ll fail-safe? function that guarantees a high level receiver output if the receiver inputs are unconnected (floating), shorte d together, or if the bus is terminated but undriven (i.e., differential voltage collapses to near zero due to termination). failsafe with shorted, or terminated and undriven inputs is accomplished by setting the rx upper switching point at -40mv, thereby ensuring that the rx recognizes a 0v differential as a high level. all the rx outputs are short circuit protected, and are tri- statable via the active high rxen pin, or when the ic is shutdown (see tables 2 and 3, and the ?low power shutdown? section). isl41387 (qfn) receiver outputs are also tri-statable via an active low rxen input (see ?isl41387 special features? for more details). for the isl41387 (qfn), when using the active high rxen function, the rxen pin may be left floating (internally pulled high), or should be connected to v cc through a 1k ? resistor. if using the active low rxen , then the rxen pin must be connected to gnd. tx features the rs-485/422 driver is a diff erential output device that delivers at least 2.2v across a 54 ? load (rs-485), and at least 2.5v across a 100 ? load (rs-422). both levels significantly exceed the sta ndards requirements, and these exceptional output voltages increase system noise immunity, and/or allow for transmission over longer distances. the drivers feature low propagation delay skew to maximize bit widths, and to minimize emi. to allow multiple drivers on a bus, the rs-485 spec requires that drivers survive worst ca se bus contentions undamaged. the islx1387 drivers meet th is requirement via driver output short circuit current limits, and on-chip thermal shutdown circuitry. the output stages incorporate current limiting circuitry that ensures that the output current never exceeds the rs-485 spec, even at the common mode voltage range extremes. in the event of a major short circuit condition, devices also include a thermal shutdown feature that disables the drivers w henever the die temperature becomes excessive. this eliminates the power dissipation, allowing the die to cool. the drivers automatically re-enable after the die temperature drops about 15 degrees. if the contention persists, the ther mal shutdown/re-enable cycle repeats until the fault is clear ed. receivers stay operational during thermal shutdown. rs-485 multi-driver operation also requires drivers to include tri-state functionality, so the port has a den pin to control this function. if the driver is used in an rs-422 network, such that driver tri-state isn?t required, then the den pin should connect to v cc through a 1k ? resistor. drivers are also tri- stated when the ic is in shdn, or when the 5v power supply is off. speed options the ISL81387 (soic/ssop) f eatures two speed options that are user selectable via the slew pin: a high slew rate setting optimized for 20mbps data rates (fast), and a slew rate limited option for operation up to 460kbps (med). the isl41387 (qfn) offers an additional, more slew rate limited, option for data rates up to 115kbps (slow). see the ?data rate? and ?slew rate limited da ta rates? sections for more information. receiver performance is the same for all three speed options. data rate, cables, and terminations rs-485/422 are intended for network lengths up to 4000? (1220m), but the maximum system data rate decreases as the transmission length increase s. devices operating at the maximum data rate of 20mbps are limited to lengths of 20- 30? (6-9m), while devices operating at or below 115kbps can operate at the maximum length of 4000? (1220m). higher data rates require faster edges, so both the islx1387 versions offer an edge rate capable of 20mbps data rates. they both have a second option for 460kbps, but the isl41387 also offers another, very slew rate limited, edge rate to minimize problems at slow data rates. nevertheless, for the best jitter performance when driving long cables, the faster speed settings may be preferable, even at low data rates. see the ?rs-485 slew rate limited data rates? section for details. twisted pair is the cable of choice for rs-485/422 networks. twisted pair cables tend to pick up noise and other electromagnetically induced voltages as common mode signals, which are effectively rejected by the differential receivers in these ics. the preferred cable connection technique is ?daisy- chaining?, where the cable runs from the connector of one device directly to the connector of the next device, such that cable stub lengths are negligib le. a ?backbone? structure, where stubs run from the main backbone cable to each device?s connector, is the next best choice, but care must be taken to ensure that each stub is electrically ?short?. see table 4 for recommended maximum stub lengths for each speed option. table 4. recommended stub lengths speed option maximum stub length ft (m) slow 350-500 (107-152) med 100-150 (30.5 - 46) fast 1-3 (0.3 - 0.9) ISL81387, isl41387
16 fn6201.1 december 20, 2005 proper termination is imperative to minimize reflections when using the 20mbps speed option. short networks using the medium and slow speed options need not be terminated, but terminations are recommended unless power dissipation is an overriding concern. note that the rs-485 spec allows a maximum of two terminations on a network, otherwise the tx output voltage may not meet the required v od . in point-to-point, or point-to -multipoint (rs-422) networks, the main cable should be terminated in its characteristic impedance (typically 120 ? ) at the end farthest from the driver. in multi-receiver applications, stubs connecting receivers to the main cable should be kept as short as possible, but definitely shorter than the limits shown in table 4. multipoint (rs-485) systems require that the main cable be terminated in its characteri stic impedance at both ends. again, keep stubs connecting a transceiver to the main cable as short as possible, and refer to table 4. avoid ?star?, and other configurations, wh ere there are many ?ends? which would require more than the two allowed terminations to prevent reflections. high esd all pins on the islx1387 include esd protection structures rated at 4kv (hbm), which is good enough to survive esd events commonly seen during manufacturing. but the bus pins (tx outputs and rx inputs) are particularly vulnerable to esd events because they connect to an exposed port on the exterior of the finished pro duct. simply touching the port pins, or connecting a cable, can destroy an unprotected port. islx1387 bus pins are fitted wi th advanced structures that deliver esd protection in excess of 15kv (hbm), without interfering with any signal in the rs-485 or the rs-232 range. this high level of pr otection may eliminate the need for board level protection, or at the very least will increase the robustness of any board level scheme. small packages many competing dual protocol ics are available only in monstrously large 24 to 28 ld soic packages. the ISL81387?s 20 ld ssop is more than 50% smaller than even a 24 ld soic, and the isl41387?s tiny 6x6mm qfn is 80% smaller than a 28 ld soic. flow through pinouts even the islx1387 pinouts are features, in that the ?flow- through? design simplifies board layout. having the bus pins all on one side of the package for easy routing to a cable connector, and the rx outputs and tx inputs on the other side for easy connection to a uart, avoids costly and problematic crossovers. figure 10 illustrates the flow- through nature of the pinout. low power shutdown (shdn) mode the islx1387 enter the shdn mode when on = 0, and the tx and rx are disabled (den = 0, rxen = 0, and rxen = 1), and the already low supply current drops to as low as 5 a. shdn disables the tx and rx outputs, and disables the charge pumps if the port is in rs-232 mode, so v+ collapses to v cc , and v- collapses to gnd. all but 5a of shdn i cc current is due to control input (spb, slew, rxen ) pull-up resistors (~20 a/resistor), so shdn i cc varies depending on the islx1387 configuration. the spec tables indicate the worst case values, but careful selection of the configuration yields lower currents. for example, in rs-232 mode the spb pin isn?t used, so floating it or tying it high minimizes shdn i cc . on the isl41387, the shdn i cc increases as v l decreases. v l powers each control pin input stage and sets its v oh at v l rather than v cc . v cc powers the second stage, but the second stage input isn?t driven to the rail, so some i cc current flows. see figure 20 for details. when enabling from shdn in rs-232 mode, allow at least 20 s for the charge pumps to stabilize before transmitting data. if fast enables are required, and i cc isn?t the greatest concern, disable the drivers with the den pin to keep the charge pumps active. the charge pumps aren?t used in rs-485 mode, so the transceiver is ready to send or receive data in less than 1 s, which is much faster than competing devices that require the charge pump for all modes of operation. internal loopback mode setting on = 0, den = 1, and rxen = 1 or rxen = 0 (qfn only), places the port in the loopback mode, a mode that facilitates implementing board level self test functions. in loopback, internal switches disconnect the rx inputs from the rx outputs, and feed back the tx outputs to the appropriate rx output. this way the data driven at the tx input appears at the corresponding rx output (refer to ?typical operating circuits?). the tx outputs remain connected to their terminals, so the external loads are reflected in the loopback performance. this allows the loopback function to potentially detect some common bus faults such as one or both dr iver outputs short ed to gnd, or outputs shorted together. note that the loopback mode uses an additional set of receivers, as shown in the ?typical operating circuits?. uart or asic or controller ra dy y z a b connector ISL81387 figure 10. illustration of flow through pinout d r ISL81387, isl41387
17 fn6201.1 december 20, 2005 these loopback receivers are not standards compliant, so the loopback mode can?t be used to implement a half-duplex rs-485 transceiver. isl41387 (qfn package) special features logic supply (v l pin) the isl41387 (qfn) includes a v l pin that powers the logic inputs (tx inputs and control pins) and rx outputs. these pins interface with ?logic? devices such as uarts, asics, and controllers, and today most of these devices use power supplies significantly lower than 5v. thus, a 5v output level from a 5v powered dual protocol ic might seriously overdrive and damage the logic device input. similarly, the the logic device?s low v oh might not exceed the v ih of a 5v powered dual protocol input. connecting the v l pin to the power supply of the logic device - as shown in figure 11 - limits the isl41387?s rx output v oh to v l (see figure 14), and reduces the tx and control input switching points to values compatible with the logic device output levels. tailoring the logic pin input switching points and output levels to the supply voltage of the uart, asic, or controller eliminates the need for a level shifter/translator between the two ics. v l can be anywhere from v cc down to 1.65v, but the input switching points may not provide enough noise margin when v l < 1.8v. table 5 indicates typical v ih and v il values for various v l values so the user can ascertain whether or not a particular v l voltage meets his needs. the v l supply current (i l ) is typically less than 60 a, as shown in figures 19 and 20. all of the dc v l current is due to inputs with internal pull-up resistors (spb, slew, rxen ) being driven to the low input state. the worst case i l current occurs when all three of the inputs are low (see figure 19), due to the i l through the pull-up resistors. i il through an input pull-up resistor is ~20 a, so the i l in figure 19 drops by about 40 a (at v l = 5v) when the spb is high and 232 mode disables the slew pin pull-up (middle vs. top curve). when all three inputs are driven high, i l drops to ~10na, so to minimize power dissipation drive these inputs high when unneeded (e.g., spb isn?t used in rs-232 mode, so drive it high). active low rx enable (rxen) in many rs-485 applications, especially half duplex configurations, users like to accomplish ?echo cancellation? by disabling the corresponding receiver while its driver is transmitting data. this functi on is available on the qfn package via an active low rxen pin. the active low function also simplifies direction control, by allowing a single tx/rx direction control line. if the active high rxen were used, either two valuable i/o pins would be used for direction control, or an external invert er is required between den and rxen. figure 12 details the advantage of using the rxen pin. when using rxen , ensure that rxen is tied to gnd. rs-485 slew rate limited data rates the islx1387 fast speed option (slew = high) utilizes tx output transitions optimized for a 20mbps data rate. these fast edges may increase emi and reflection issues, even though fast transitions aren?t required at the lower data rates used by many applications. with the slew pin low, both product types switch to a modera tely slew rate limited output transition targeted for 460kbps (med) data rates. the isl41387 (qfn version) offers an additional, slew rate limited data rate that is optimized for 115kbps (slow), and is selected when slew = 0 an d spb = 0 (see table 3). the slew limited edges permit longer unterminated networks, or longer stubs off terminated busses, and help minimize emi and reflections. nevertheless, for the best jitter performance when driving long cables, the faster speed options may be preferable, even at lower data rates. the faster output transitions deliver less variability (jitter) when loaded with the figure 11. using v l pin to adjust logic levels gnd r xd t xd v cc = +2v uart/processor gnd r a d y v cc = +5v ISL81387 v oh 2v v oh = 5v v ih 2v esd diode gnd r xd t xd v cc = +2v uart/processor gnd r a d y v cc = +5v isl41387 v oh 2v v oh = 2v v ih = 0.9v esd diode v l table 5. v ih and v il vs. v l for v cc = 5v v l (v) v ih (v) v il (v) 1.65v 0.79 0.50 1.8v 0.82 0.60 2.0v 0.87 0.69 2.5v 0.99 0.86 3.3v 1.19 1.05 ISL81387, isl41387
18 fn6201.1 december 20, 2005 large capacitance associated with long cables. figures 42, 43, and 44 detail the jitter performance of the three speed options while driving three different cable lengths. the figures show that under all c onditions the faster the edge rate, the better the jitter performance. of course, faster transitions require more atte ntion to ensuring short stub lengths, and quality terminations , so there are trade-offs to be made. assuming a jitter budget of 10%, it is likely better to go with the slow speed option for data rates of 115kbps or less, to minimize fast edge effects. likewise, the medium speed option is a good choice for data rates between 115kbps and 460kbps. for higher data rates, or when the absolute best jitter is required, use the high speed option. evaluation board an evaluation board, part number isl41387eval1, is available to assist in assessing the dual protocol ic?s performance. the evaluation board contains a qfn packaged device, but because the same die is used in all packages, the board is also useful for evaluating the functionality of the other versions. the board?s design allows for evaluation of all standard fe atures, plus the qfn specific features. refer to the eval boar d application note for details, and contact your sales rep for ordering information. figure 12. using active low vs active high rx enable 0.1 f + d r v cc gnd ra rxen den dy +5v isl41387 tx/rx active high rx enable 0.1 f + d r v cc gnd ra rxen * den dy +5v isl41387 tx/rx * qfn only active low rx enable rxen 1k ? or nc rxen * y z a b y z a b ISL81387, isl41387
19 fn6201.1 december 20, 2005 typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified figure 13. receiver output current vs receiver output voltage figure 14. receiver high output voltage vs logic supply voltage (v l ) figure 15. rs-485, driver output current vs differential output voltage figure 16. rs-485, driver differential output voltage vs temperature figure 17. rs-485, driver output current vs short circuit voltage figure 18. supply current vs temperature 012345 0 10 20 30 40 50 receiver output voltage (v) receiver output current (ma) v oh , 25 c v oh , 85 c v ol , 25 c v ol , 85 c v l (v) high output voltage (v) 012345 0 1 2 3 4 5 i oh = -1ma i oh = -4ma i oh = -8ma differential output voltage (v) driver output current (ma) 012345 0 10 20 30 40 50 60 70 80 90 100 -40 0 50 85 temperature (c) differential output voltage (v) -25 25 75 r diff = 54 ? r diff = 100 ? 3 3.1 3.2 3.3 3.4 3.5 3.6 output voltage (v) -7 -6 -4 -2 0 2 4 6 8 10 12 output current (ma) -150 -100 -50 0 50 100 150 y or z = high y or z = low 25c 85c -40c full temp range -40 0 50 85 temperature (c) i cc (ma) -25 25 75 1 1.5 2 2.5 3 3.5 4 rs-232, rxen , rxen, on = x, den = v cc rs-485, den = gnd, rxen , rxen = x, on = v cc rs-485, half duplex, den = v cc , rxen , rxen, on = x rs-485, full duplex, den = v cc , rxen , rxen, on = x rs-232, rxen , rxen = x, on = v cc , den = gnd ISL81387, isl41387
20 fn6201.1 december 20, 2005 figure 19. rs-232, v l supply current vs v l voltage (qfn only) figure 20. v cc and v l shdn supply currents vs v l voltage (qfn only) figure 21. rs-485, driver propagation delay vs temperature (slow data rate, qfn only) figure 22. rs-485, driver skew vs temperature (slow data rate, qfn only) figure 23. rs-485, driver propagation delay vs temperature (medium data rate, qfn only) figure 24. rs-485, driver skew vs temperature (medium data rate, qfn only) typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) i l (a) v l (v) 1 10 100 10m 1m 23456 v l v cc v l > v cc 100n 10n 1n rs-485, slew, spb, rxen = v l no load v in = v l or gnd rs-232, spb, rxen = v l or rs-485, slew, spb, rxen = gnd rs-232, rxen = gnd, spb = v l den, rxen, on = gnd 22.533.544.55 i cc and i l (ma) v l (v) 0 100 200 300 400 500 no load v in = v l or gnd rxen = v l rs-232/rs-485 i cc spb = gnd spb = v l rs-232 i l rs-485 i l den, rxen, dy, dz/slew, on = gnd -40 0 50 85 temperature (c) -25 25 75 propagation delay (ns) 1400 1450 1500 1550 1600 1650 1700 t dlh t dhl r diff = 54 ? , c l = 100pf t dhl -40 0 50 85 temperature (c) skew (ns) -25 25 75 400 |t plhz - t phly | |t phlz - t plhy | |t dlh - t dhl | r diff = 54 ? , c l = 100pf 50 100 150 200 250 300 350 -40 0 50 85 temperature (c) -25 25 75 propagation delay (ns) 470 480 490 500 510 520 530 540 550 560 t dlh t dhl t dhl r diff = 54 ? , c l = 100pf -40 0 50 85 temperature (c) skew (ns) -25 25 75 0 20 40 60 80 100 120 r diff = 54 ? , c l = 100pf |t phlz - t plhy | |t plhz - t phly | |t dlh - t dhl | ISL81387, isl41387
21 fn6201.1 december 20, 2005 figure 25. rs-485, driver propagation delay vs temperature (fast data rate) figure 26. rs-485, driver skew vs temperature (fast data rate) figure 27. rs-485, driver and receiver waveforms, low to high (slow data rate, qfn only) figure 28. rs-485, driver and receiver waveforms, high to low (slow data rate, qfn only ) figure 29. rs-485, driver and receiver waveforms, low to high (medium data rate, qfn only) figure 30. rs-485, driver and receiver waveforms, high to low (medium data rate, qfn only ) typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) -40 0 50 85 temperature (c) -25 25 75 t dlh t dhl propagation delay (ns) 20 25 30 35 40 r diff = 54 ? , c l = 100pf -40 0 50 85 temperature (c) skew (ns) -25 25 75 0 0.5 1 1.5 2 2.5 r diff = 54 ? , c l = 100pf |t plhz - t phly | |t phlz - t plhy | |t dlh - t dhl | time (400ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (400ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (200ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (200ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y ISL81387, isl41387
22 fn6201.1 december 20, 2005 figure 31. rs-485, driver and receiver waveforms, low to high (fast data rate) figure 32. rs-485, driver and receiver waveforms, high to low (fast data rate ) figure 33. rs-232, transmitter output voltage vs load capacitance figure 34. rs-232, transmitter output voltage vs temperature figure 35. rs-232, transmitter short circuit current vs temperature figure 36. rs-232, transmitter and receiver waveforms at 250kbps typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) time (10ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (10ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y -7.5 -5 -2.5 2.5 7.5 1000 2000 3000 4000 5000 0 load capacitance (pf) transmitter output voltage (v) rs-232 region of noncompliance 0 5 1 transmitter at 250kbps or 500kbps, v out + v out - other transmitter at 30kbps 500kbps 500kbps 250kbps 250kbps all t outs loaded with 3k ? to gnd -40 0 50 85 temperature (c) transmitter output voltage (v) -25 25 75 -7.5 -5 0 5 7.5 2.5 -2.5 v out + v out - outputs static all t outs loaded with 3k ? to gnd -40 0 50 85 temperature (c) transmitter output current (ma) -25 25 75 -40 -30 -20 -10 0 10 20 30 40 y or z = high y or z = low v out shorted to gnd 2 s/div. c l = 3500pf, 2 channels switching y/a 0 -5 0 5 0 5 5 ra dy ISL81387, isl41387
23 fn6201.1 december 20, 2005 figure 37. rs-232, transmitter and receiver waveforms at 500kbps figure 38. rs-232, receiver output +duty cycle vs data rate figure 39. rs-232, transmitter maximum data rate vs load capacitance figure 40. rs-232, transmitter output voltage vs data rate figure 41. rs-232, transmitter skew vs data rate figure 42. rs-485, transmitter jitter vs data rate with 2000? cat 5 cable typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) 1 s/div. c l = 1000pf, 2 channels switching y/a 0 -5 0 5 0 5 5 ra dy 500 1000 1500 2000 48 50 52 54 56 58 60 data rate (kbps) receiver + duty cycle (%) full temp range sr in = 15v/ s sr in = 100v/ s 50 v in = 5v 100 1000 2000 3000 4000 5000 100 200 300 400 500 600 700 800 900 1000 1100 load capacitance (pf) data rate (kbps) 2 transmitters at 25c 2 transmitters at 85c 1 transmitter at 25c v out 4v all t outs loaded with 5k ? to gnd 1 transmitter at 85c 0 100 200 300 400 500 600 700 800 -7.5 -5 0 5 7.5 2.5 -2.5 data rate (kbps) transmitter output voltage (v) 25 c 85 c 25 c 85 c v out + v out - 2 transmitters switching all t outs loaded with 5k ? to gnd, c l = 1000pf rs-232 region of noncompliance 50 150 250 350 450 550 650 750 150 200 250 300 350 400 450 data rate (kbps) skew (ns) 25c 85c all t outs loaded with 3k ? to gnd, c l = 1000pf 2 transmitters switching data rate (kbps) jitter (%) 32 100 200 300 400 500 600 700 800 900 1000 0.1 1 10 100 double term?ed with 121 ? slow med fast ISL81387, isl41387
24 fn6201.1 december 20, 2005 die characteristics substrate potential (powered up): gnd transistor count: 2490 process: bicmos figure 43. rs-485, transmitter jitter vs data rate with 1000? cat 5 cable figure 44. rs-485, transmitter jitter vs data rate with 350? cat 5 cable typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) data rate (kbps) jitter (%) 32 100 200 300 400 500 600 700 800 900 1000 0.1 1 10 100 double term?ed with 121 ? slow med fast data rate (kbps) jitter (%) 32 100 200 300 400 500 600 700 800 900 1000 0.1 1 10 100 double term?ed with 121 ? slow med fast ISL81387, isl41387
25 fn6201.1 december 20, 2005 ISL81387, isl41387 small outline plast ic packages (soic) notes: 1. symbols are defined in the ?mo series symbol list? in section 2.2 of publication number 95. 2. dimensioning and tolerancing per ansi y14.5m - 1982. 3. dimension ?d? does not include mold flash, protrusions or gate burrs. mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 4. dimension ?e? does not include interlead flash or protrusions. interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 5. the chamfer on the body is optional. if it is not present, a visual index feature must be located within the crosshatched area. 6. ?l? is the length of terminal for soldering to a substrate. 7. ?n? is the number of terminal positions. 8. terminal numbers are shown for reference only. 9. the lead width ?b?, as measured 0.36mm (0.014 inch) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch) 10. controlling dimension: millimeter. converted inch dimensions are not necessarily exact. index area e d n 123 -b- 0.25(0.010) c a m b s e -a- l b m -c- a1 a seating plane 0.10(0.004) h x 45 c h 0.25(0.010) b m m m20.3 (jedec ms-013-ac issue c) 20 lead wide body small outline plastic package symbol inches millimeters notes min max min max a 0.0926 0.1043 2.35 2.65 - a1 0.0040 0.0118 0.10 0.30 - b 0.014 0.019 0.35 0.49 9 c 0.0091 0.0125 0.23 0.32 - d 0.4961 0.5118 12.60 13.00 3 e 0.2914 0.2992 7.40 7.60 4 e 0.050 bsc 1.27 bsc - h 0.394 0.419 10.00 10.65 - h 0.010 0.029 0.25 0.75 5 l 0.016 0.050 0.40 1.27 6 n20 207 0 8 0 8 - rev. 2 6/05
26 fn6201.1 december 20, 2005 ISL81387, isl41387 shrink small outline plastic packages (ssop) notes: 1. symbols are defined in the ?mo series symbol list? in section 2.2 of publication number 95. 2. dimensioning and tolerancing per ansi y14.5m - 1982. 3. dimension ?d? does not include mold flash, protrusions or gate burrs. mold flash, protrusion and gate burrs shall not exceed 0.20mm (0.0078 inch) per side. 4. dimension ?e? does not include interlead flash or protrusions. in- terlead flash and protrusions shall not exceed 0.20mm (0.0078 inch) per side. 5. the chamfer on the body is optional. if it is not present, a visual index feature must be located within the crosshatched area. 6. ?l? is the length of terminal for soldering to a substrate. 7. ?n? is the number of terminal positions. 8. terminal numbers are shown for reference only. 9. dimension ?b? does not include dambar protrusion. allowable dambar protrusion shall be 0.13mm (0.005 inch) total in excess of ?b? dimension at maximum material condition. 10. controlling dimension: millimeter. converted inch dimen- sions are not necessarily exact. index area e d n 123 -b- 0.25(0.010) c a m b s e -a- b m -c- a1 a seating plane 0.10(0.004) c h 0.25(0.010) b m m l 0.25 0.010 gauge plane a2 m20.209 (jedec mo-150-ae issue b) 20 lead shrink small outline plastic package symbol inches millimeters notes min max min max a 0.068 0.078 1.73 1.99 a1 0.002 0.008? 0.05 0.21 a2 0.066 0.070? 1.68 1.78 b 0.010? 0.015 0.25 0.38 9 c 0.004 0.008 0.09 0.20? d 0.278 0.289 7.07 7.33 3 e 0.205 0.212 5.20? 5.38 4 e 0.026 bsc 0.65 bsc h 0.301 0.311 7.65 7.90? l 0.025 0.037 0.63 0.95 6 n20 207 0 deg. 8 deg. 0 deg. 8 deg. rev. 3 11/02
27 all intersil u.s. products are manufactured, asse mbled and tested utilizing iso9000 quality systems. intersil corporation?s quality certifications ca n be viewed at www.intersil.com/design/quality intersil products are sold by description only. intersil corpor ation reserves the right to make changes in circuit design, soft ware and/or specifications at any time without notice. accordingly, the reader is cautioned to verify that data sheets are current before placing orders. information furnishe d by intersil is believed to be accurate and reliable. however, no responsibility is assumed by intersil or its subsidiaries for its use; nor for any infringements of paten ts or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of intersil or its subsidiari es. for information regarding intersil corporation and its products, see www.intersil.com fn6201.1 december 20, 2005 quad flat no-lead plastic package (qfn) micro lead frame pl astic package (mlfp) l40.6x6 40 lead quad flat no-lead plastic package (compliant to jedec mo-220vjjd-2 issue c) symbol millimeters notes min nominal max a 0.80 0.90 1.00 - a1 - - 0.05 - a2 - - 1.00 9 a3 0.20 ref 9 b 0.18 0.23 0.30 5, 8 d 6.00 bsc - d1 5.75 bsc 9 d2 3.95 4.10 4.25 7, 8 e 6.00 bsc - e1 5.75 bsc 9 e2 3.95 4.10 4.25 7, 8 e 0.50 bsc - k0.25 - - - l 0.30 0.40 0.50 8 l1 - - 0.15 10 n402 nd 10 3 ne 10 3 p- -0.609 --129 rev. 1 10/02 notes: 1. dimensioning and tolerancing conform to asme y14.5-1994. 2. n is the number of terminals. 3. nd and ne refer to the number of terminals on each d and e. 4. all dimensions are in millimeters. angles are in degrees. 5. dimension b applies to the meta llized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 6. the configuration of the pin #1 identifier is optional, but must be located within the zone indicated. the pin #1 identifier may be either a mold or mark feature. 7. dimensions d2 and e2 are fo r the exposed pads which provide improved electrical and thermal performance. 8. nominal dimensions are provided to assist with pcb land pattern design efforts, see intersil technical brief tb389. 9. features and dimensions a2, a3, d1, e1, p & are present when anvil singulation method is used and not present for saw singulation. 10. depending on the method of lead termination at the edge of the package, a maximum 0.15mm pull back (l1) maybe present. l minus l1 to be equal to or greater than 0.3mm. ISL81387, isl41387

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