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ICS557-03 PCI-EXPRESS CLOCK SOURCE Description The ICS557-03 is a spread spectrum clock generator supporting PCI-Express and Ethernet requirements. The device is used for PC or embedded systems to substantially reduce electromagnetic interference (EMI). The device provides two differential (HCSL) spread spectrum outputs. This device is pin configured to select spread and clock selection. Using ICS' patented Phase-Locked Loop (PLL) techniques, the device takes a 25 MHz crystal input and produces two pairs of differential outputs (HCSL) at 25 MHz, 100 MHz, 125 MHz and 200 MHz clock frequencies. It also provides spread selection of 0.25%, -0.5%, -0.75%, and no spread. Features * * * * * * * * * Packaged in 16-pin TSSOP Available in Pb (lead) free package Supports LVDS Output Levels Operating voltage of 3.3 V Input frequency of 25 MHz Outputs (HCSL, 0.7 V Current mode differential pair) Jitter 100 ps (peak-to-peak) Spread of 0.25%, -0.5%, -0.75%, and no spread. Industrial and commercial temperature ranges Block Diagram VDD 2 SS1:SS0 S1:S0 2 CLK0 Control Logic Phase Lock Loop CLK1 CLK1 CLK0 2 X1/ICLK 25 MHz crystal or clock X2 Optional tuning crystal capacitors Clock Buffer/ Crystal Oscillator 2 GND OE Rr(IREF) MDS 557-03 E I n t e gra te d C i r c u i t S y s t e m s 1 525 Race Stre et, San Jo se, CA 9 5126 Revision 061005 te l (40 8) 2 97-12 01 w w w. i c st . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE Pin Assignment S0 S1 SS0 X1/ICLK X2 OE GNDXD SS1 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VDDXD CLK0 CLK0 GNDODA VDDODA CLK1 CLK1 IREF Output Select Table 1(MHz) S1 0 0 1 1 S0 0 1 0 1 CLK(1:0), CLK(1:0) 25M 100M 125M 200M Spread Selection Table 2 SS1 0 0 1 1 SS0 0 1 0 1 Spread % Center 0.25 Down -0.5 Down -0.75 No Spread 16-pin (173 mil) TSSOP Pin Descriptions Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Pin Name S0 S1 SS0 X1/ICLK X2 OE GNDXD SS1 IREF CLK1 CLK1 VDDODA GNDODA CLK0 CLK0 VDDXD Pin Type Input Input Input Input Input Power Input Pin Description Select pin 0. See Table1. Internal pull-up resistor. Select pin 1. See Table 1. Internal pull-up resistor. Spread Select pin 0. See Table 2. Internal pull-up resistor. Crystal or clock input. Connect to a 25 MHz crystal or single ended clock. Output enable tri-states outputs and device is not shut down. Internal pull-up resistor. Connect to ground. Spread Select pin 1. See Table 2. Internal pull-up resistor. Output Crystal connection. Leave unconnected for clock input. Output Precision resistor attached to this pin is connected to the internal current reference. Output HCSL compliment clock output. Output HCSL clock output. Power Power Connect to voltage supply +3.3 V for output driver and analog circuits Connect to ground. Output HCSL compliment clock output. Output HCSL clock output. Power Connect to voltage supply +3.3 V for crystal oscillator and digital circuit. MDS 557-03 E In te grated Circuit Systems 2 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE Applications Information External Components A minimum number of external components are required for proper operation. Output Structures IREF =2.3 mA 6*IREF Decoupling Capacitors Decoupling capacitors of 0.01 F should be connected between each VDD pin and the ground plane, as close to the VDD pin as possible. Do not share ground vias between components. Route power from power source through the capacitor pad and then into ICS pin. Crystal A 25 MHz fundamental mode parallel resonant crystal should be used. This crystal must have less than 300 ppm of error across temperature in order for the ICS557-03 to meet PCI Express specifications. R R 475 See Output Termination Sections - Pages 3 ~ 5 Crystal Capacitors Crystal capacitors are connected from pins X1 to ground and X2 to ground to optimize the accuracy of the output frequency. CL= Crystal's load capacitance in pF Crystal Capacitors (pF) = (CL- 8) * 2 For example, for a crystal with a 16 pF load cap, each external crystal cap would be 16 pF. (16-8)*2=16. General PCB Layout Recommendations For optimum device performance and lowest output phase noise, the following guidelines should be observed. 1. Each 0.01F decoupling capacitor should be mounted on the component side of the board as close to the VDD pin as possible. 2. No vias should be used between decoupling capacitor and VDD pin. 3. The PCB trace to VDD pin should be kept as short as possible, as should the PCB trace to the ground via. Distance of the ferrite bead and bulk decoupling from the device is less critical. 4. An optimum layout is one with all components on the same side of the board, minimizing vias through other signal layers (any ferrite beads and bulk decoupling capacitors can be mounted on the back). Other signal traces should be routed away from the ICS557-03.This includes signal traces just underneath the device, or on layers adjacent to the ground plane layer used by the device. Current Source (Iref) Reference Resistor - RR If board target trace impedance (Z) is 50, then RR = 475 (1%), providing IREF of 2.32 mA. The output current (IOH) is equal to 6*IREF. Output Termination The PCI-Express differential clock outputs of the ICS557-03 are open source drivers and require an external series resistor and a resistor to ground. These resistor values and their allowable locations are shown in detail in the PCI-Express Layout Guidelines section. The ICS557-03 can also be configured for LVDS compatible voltage levels. See the LVDS Compatible Layout Guidelines section. MDS 557-03 E In te grated Circuit Systems 3 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE PCI-Express Layout Guidelines Common Recommendations for Differential Routing L1 length, Route as non-coupled 50 ohm trace. L2 length, Route as non-coupled 50 ohm trace. L3 length, Route as non-coupled 50 ohm trace. RS RT Differential Routing on a Single PCB L4 length, Route as coupled microstrip 100 ohm differential trace. L4 length, Route as coupled stripline 100 ohm differential trace. Differential Routing to a PCI Express Connector L4 length, Route as coupled microstrip 100 ohm differential trace. L4 length, Route as coupled stripline 100 ohm differential trace. Dimension or Value 0.5 max 0.2 max 0.2 max 33 49.9 Dimension or Value 2 min to 16 max 1.8 min to 14.4 max Dimension or Value 0.25 to 14 max 0.225 min to 12.6 max Unit inch inch inch ohm ohm Unit inch inch Unit inch inch PCI-Express Device Routing L1 RS L1' RS L2 L2' RT L3' RT L3 L4 L4' ICS557-03 Output Clock PCI-Express Load or Connector Typical PCI-Express (HCSL) Waveform 700 mV 0 tOR 0.52 V 0.175 V 500 ps 500 ps tOF 0.52 V 0.175 V MDS 557-03 E In te grated Circuit Systems 4 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE LVDS Compatible Layout Guidelines LVDS Recommendations for Differential Routing L1 length, Route as non-coupled 50 ohm trace. L2 length, Route as non-coupled 50 ohm trace. RP RQ RT L3 length, Route as coupled 50 ohm differential trace. L3 length, Route as coupled 50 ohm differential trace. Dimension or Value 0.5 max 0.2 max 100 100 150 Unit inch inch ohm ohm ohm LVDS Device Routing L1 RQ L1' L3 L3' RP RT ICS557-03 Clock Output L2' L2 RT LVDS Device Load Typical LVDS Waveform 1325 mV 1000 mV tOR 500 ps 500 ps tOF 1250 mV 1150 mV 1250 mV 1150 mV MDS 557-03 E In te grated Circuit Systems 5 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE Absolute Maximum Ratings Stresses above the ratings listed below can cause permanent damage to the ICS557-03. These ratings are stress ratings only. Functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical parameters are guaranteed only over the recommended operating temperature range. Item Supply Voltage, VDD, VDDA All Inputs and Outputs Ambient Operating Temperature (commercial) Ambient Operating Temperature (industrial) Storage Temperature Junction Temperature Soldering Temperature ESD Protection (Input) 5.5 V Rating -0.5 V to VDD+0.5 V 0 to +70C -40 to +85C -65 to +150C 125C 260C 2000 V min. (HBM) DC Electrical Characteristics Unless stated otherwise, VDD = 3.3 V 10%, Ambient Temperature -40 to +85C Parameter Supply Voltage Input High Voltage 1 Symbol V VIH VIL IIL IDD IDDOE CIN COUT LPIN ROUT RPU CLKOUT Conditions S0, S1, OE, CLK, SS0, SS1 S0, S1, OE, CLK, SS0, SS1 0 < Vin < VDD 50, 2pF OE =Low Input pin capacitance Output pin capacitance Min. 2.97 2.0 VSS-0.3 -5 Typ. 3.3 Max. 3.63 VDD +0.3 0.8 5 65 35 7 6 5 Units V V A mA mA pF pF nH k k Input Low Voltage1 Input Leakage Current2 Operating Supply Current Input Capacitance Output Capacitance Pin Inductance Output Resistance Pull-up Resistor 3.0 100 region. 1 Single edge is monotonic when transitioning through 2 Inputs with pull-ups/-downs are not included. MDS 557-03 E In te grated Circuit Systems 6 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE AC Electrical Characteristics - CLK0/CLK1, CLK0/CLK1 Unless stated otherwise, VDD=3.3 V 10%, Ambient Temperature -40 to +85C Parameter Input Frequency Output Frequency Output High Voltage Output Low Voltage Crossing Point Voltage1,2 Crossing Point Voltage1,2,4 Jitter, Cycle-to-Cycle1,3 Modulation Frequency Rise Time1,2 Fall Time 1,2 1,2 Symbol Conditions Min. 25 Typ. 25 Max. 200 Units MHz MHz mV mV mV mV ps VOH VOL Notes 1, 2 Notes 1, 2 Absolute, Notes 1, 2 Variation over all edges, Notes 1, 2, 4 Notes 1, 3 Spread spectrum 660 -150 250 700 0 350 850 550 140 1,2 60 30 175 175 31.5 332 344 33 700 700 125 50 45 10 10 3.0 3.0 55 kHz ps ps ps ps % us us ms ms tOR tOF From 0.175 V to 0.525 V, Notes 1, 2 From 0.525 V to 0.175 V, Notes 1, 2 Notes 1, 2 At VDD/2 Notes 1, 3 All outputs, Note 5 All outputs, Note 5 Rise/Fall Time Variation1,2 Skew between outputs Duty Cycle1,3 Output Enable Time Stabilization Time Spread Change Time 5 5 Output Disable Time tSTABLE From power-up VDD=3.3 V tSPREAD Settling period after spread change Note 1: Test setup is RL=50 ohms with 2 pF, Rr = 475 (1%). Note 2: Measurement taken from a single-ended waveform. Note 3: Measurement taken from a differential waveform. Note 4: Measured at the crossing point where instantaneous voltages of both CLK and CLK are equal. Note 5: CLK pins are tri-stated when OE is low asserted. CLK is driven differential when OE is high. MDS 557-03 E In te grated Circuit Systems 7 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE Thermal Characteristics Parameter Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case Symbol JA JA JA JC Conditions Still air 1 m/s air flow 3 m/s air flow Min. Typ. 78 70 68 37 Max. Units C/W C/W C/W C/W Marking Diagram (ICS557G-03) 16 9 Marking Diagram (ICS557GI-03) 16 9 IC ###### S YYWW 557G-03 8 IC ###### S YYWW 557GI-03 8 1 1 Marking Diagram (ICS557G-03LF) 16 9 Marking Diagram (ICS557GI-03LF) 16 9 IC ###### S YYWW 557G03LF 8 IC ###### S YYWW 557GI03L 8 1 1 Notes: 1. ###### is the lot code. 2. YYWW is the last two digits of the year, and the week number that the part was assembled. 3. "LF" designates Pb (lead) free package. 4. "I" deisgnates industrial temperature range. 5. Bottom marking: (origin). Origin = country of origin of not USA. MDS 557-03 E In te grated Circuit Systems 8 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m ICS557-03 PCI-EXPRESS CLOCK SOURCE Package Outline and Package Dimensions (16-pin TSSOP, 173 Mil. Narrow Body) Package dimensions are kept current with JEDEC Publication No. 95 16 Millimeters Symbol Min Max Inches Min Max E1 INDEX AREA E 12 D A2 A1 A A A1 A2 b C D E E1 e L aaa -1.20 0.05 0.15 0.80 1.05 0.19 0.30 0.09 0.20 4.90 5.1 6.40 BASIC 4.30 4.50 0.65 Basic 0.45 0.75 0 8 -0.10 -0.047 0.002 0.006 0.032 0.041 0.007 0.012 0.0035 0.008 0.193 0.201 0.252 BASIC 0.169 0.177 0.0256 Basic 0.018 0.030 0 8 -0.004 c -Ce b SEATING PLANE L aaa C Ordering Information Part / Order Number ICS557G-03 ICS557G-03T ICS557G-03LF ICS557G-03LFT ICS557GI-03 ICS557GI-03T ICS557GI-03LF ICS557GI-03LFT See Page 8 Marking See Page 8 Shipping Packaging Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Package 16-pin TSSOP 16-pin TSSOP 16-pin TSSOP 16-pin TSSOP 16-pin TSSOP 16-pin TSSOP 16-pin TSSOP 16-pin TSSOP Temperature 0 to +70 C 0 to +70 C 0 to +70 C 0 to +70 C -40 to +85 C -40 to +85 C -40 to +85 C -40 to +85 C Parts that are ordered with a "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant. While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS) assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or critical medical instruments. MDS 557-03 E In te grated Circuit Systems 9 525 Ra ce Street, San Jose, CA 9512 6 Revision 061005 tel (4 08) 297-1 201 w w w. i c s t . c o m |
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