1 www.pericom.com 04/29/1 1 product features ? lvds compatible outputs ? supply voltage of 3.3v 10% ? 25mhz input frequency ? hcsl outputs, 0.7v current mode diferential pair ? jitter 60ps cycle-to-cycle (typ) ? spread of 0.25%, -0.5%, -0.75%, and no spread ? industrial temperature range ? packaging: (pb-free and green) 1 6-pin, 173 mils wide tssop pi6c557-03 pci express clock description te pi6c557-03 is a spread spectrum clock generator supporting pci express and ethernet requirements. te device is used for pc or embedded systems to substantially reduce electromagnetic interference (emi). te pi6c557-03 provides two diferential (hcsl) spread spectrum outputs. te pi6c557-03 is confgured to select spread and clock selection. using pericom's patented phase-locked loop (pll) techniques, the device takes a 25mhz crystal input and produces two pairs of diferential outputs (hcsl) at 25mhz, 100mhz, 125mhz and 200mhz clock frequencies. it also provides spread selection of 0.25%, -0.5%, -0.75%, and no spread. block diagram 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 vddx clk0 clk0 gnda vdda clk1 clk1 iref s0 s1 ss0 x1/clk x2 oe gndx ss1 pin configuration phase lock loop crystal driver vdd gnd x1/clk x2 25 mhz crystal or clock control logic ss1:ss0 2 s1:s0 2 clk0 clk0 r r clk1 clk1 2 2 oe pulling capacitors 11-0060
2 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 pin description pin # pin name i/o type description 1 s0 input select pin 0 (internal pull-up resistor). see table 1. 2 s1 input select pin 1 (internal pull-up resistor). see table 1. 3 ss0 input spread select pin 0 (internal pull-up resistor). see table 2. 4 x1/clk input crystal or clock input. connect to a 25mhz crystal or single ended clock. 5 x2 output crystal connection. leave unconnected for clock input. 6 oe input output enable. internal pull-up resistor. 7 gndx power crystal ground pin. 8 ss1 input spread select pin 1 (internal pull-up resistor). see table 2. 9 iref output precision resistor attached to this pin is connected to the internal current reference. 10 clk1 output hcsl compliment clock output 11 clk1 output hcsl clock output 12 vdda power connect to a +3.3v source. 13 gnda power output and analog circuit ground. 14 clk0 output hcsl compliment clock output 15 clk0 output hcsl clock output 16 vddx power connect to a +3.3v source. table 1: output select table s1 s0 clk(mhz) 0 0 25 0 1 100 1 0 125 1 1 200 table 2: spread selection table ss1 ss0 spread 0 0 center 0.25 0 1 down -0.5 1 0 down -0.75 1 1 no spread 11-0060
3 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 application information decoupling capacitors decoupling capacitors of 0.01f should be connected between each v dd pin and the ground plane and placed as close to the v dd pin as possible. crystal use a 25mhz fundamental mode parallel resonant crystal with less than 300ppm of error across temperature. crystal capacitors c l = crystals's load capacitance in pf crystal capacitors (pf) = (c l - 8) *2 for example, for a crystal with 16pf load caps, the external ef- fective crystal cap would be 16 pf. (16-8)*2=16. current source (iref) reference resistor - r r if board target trace impedance is 50?, then r r = 475? providing an iref of 2.32 ma. te output current (i oh ) is 6*iref. output termination te pci express diferential clock outputs of the pi6c557-03 are open source drivers and require an external series resistor and a resistor to ground. tese resistor values and their allow- able locations are shown in detail in the pci express layout guidelines section. te pi6c557-03 can be confgured for lvds compatible voltage levels. see the lvds compatible layout guidelines section. r r =475 6*iref =2.3ma iref see output termination sections ? output structures 11-0060
4 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 pci express layout guidelines common recommendations for diferential routing dimension or value unit l1 length, route as non-coupled 50? trace. 0.5 max inch l2 length, route as non-coupled 50? trace. 0.2 max inch l3 length, route as non-coupled 50? trace. 0.2 max inch r s 33 ? r t 49.9 ? diferential routing on a single pcb dimension or value unit l4 length, route as coupled microstrip 100? diferential trace. 2 min to 16 max inch l4 length, route as coupled stripline 100? diferential trace. 1.8 min to 14.4 max inch diferential routing to a pci express connector dimension or value unit l4 length, route as coupled microstrip 100? diferential trace. 0.25 min to 14 max inch l4 length, route as coupled stripline 100? diferential trace. 0.225 min to 12.6 max inch r s r s r t r t pci-express load or connector l1 l2 l3? l4 l1? l2? l3 l4? pi6c557-03 output clock 0.175 v 0.52 v 0.175 v 0.52 v t or t of 500 ps 500 ps 700 mv 0 pci express device routing typical pci express (hcsl) waveform 11-0060
5 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 application information lvds recommendations for diferential routing dimension or value unit l1 length, route as non-coupled 50? trace. 0.5 max inch l2 length, route as non-coupled 50? trace. 0.2 max inch r p 100 ? r q 100 ? r t 150 ? l3 length, route as 100? diferential trace. l3 length, route as 100? diferential trace. lvds device routing typical lvds waveform l1 l2? l3 l1? l2 l3? r q r p lvds device load pi6c557-03 clock output r t r t 1150 mv 1250 mv t or t of 500 ps 500 ps 1325 mv 1000 mv 1150 mv 1250 mv 11-0060
6 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 supply voltage to ground potential ...........................................................5 .5v all inputs and outputs ..................................................... - 0.5v to v dd +0.5v ambient operating temperature .................................................- 40 to +85c storage temperature .....................................................................- 65 to +150c junction temperature .............................................................................. 1 50c soldering temperature ............................................................................. 2 60c electrical specifications maximum ratings recommended operation conditions parameter min. typ. max. unit ambient operating temperature -40 +85 c power supply voltage (measured in respect to gnd) +3.0 +3.6 v dc characteristics (v dd = 3.3v 10%, t a = -40c to +85 c) symbol parameter conditions min. typ. max. unit v dd supply voltage 3.0 3.3 3.60 v v ih input high voltage (1) s0, s1, oe, clk, ss0, ss1 2.0 v dd +0.3 v v il input low voltage (1) s0, s1, oe, clk, ss0, ss1 gnd -0.3 0.8 v i il input leakage current 0 < vin < vdd with input pull-up and pull-downs -20 20 a without input pull-up and pull-downs -5 5 i dd operating supply current r l = 50, c l = 2pf 65 ma i ddoe oe = low 35 ma c in input capacitance input pin capacitance 7 pf c out output capacitance output pin capacitance 6 pf l pin pin inductance 5 nh r out output resistance clk outputs 3.0 k notes: 1. single edge is monotonic when transitioning through region. note: stresses greater than those listed under maximum rat- ings may cause permanent damage to the device. tis is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational sections of this specifcation is not implied. ex- posure to absolute maximum rating conditions for extended periods may afect reliability. 11-0060
7 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 ac characteristics (v dd = 3.3v 10%, t a = -40c to +85 o c) symbol parameter conditions min. typ. max. unit f in input frequency 25 mhz v out output frequency 25 200 mhz v oh output high voltage (1,2) @v dd = 3.3v 660 700 850 mv v ol output low voltage (1,2) -150 0 mv v cpa crossing point voltage (1,2) absolute 250 350 550 mv v cn crossing point voltage (1,2,4) variation over all edges 140 mv j cc jitter, cycle-to-cycle (1,3) 60 100 ps mf modulation frequency spread spectrum 30 31.5 33 khz t or rise time (1,2) from 0.175v to 0.525v 175 332 700 ps t of fall time (1,2) from 0.525v to 0.175v 175 344 700 ps ? t r /?t rise/fall time variation (1,2) 125 ps t skew skew between outputs v dd /2 50 ps t duty- cycle duty cycle (1,3) 45 55 % t oe output enable time (5) all outputs 0.1 s t ot output disable time (5) all outputs 0.1 s t stable from power-up to vdd=3.3v 1.6 3.0 ms t spread setting period afer spread change 3.0 ms notes: 1. rl = 50f with cl = 2 pf and rr = 475 2. single-ended waveform 3. diferential waveform 4. measured at the crossing point 5. clk pins are tri-stated when oe is low termal characteristics symbol parameter conditions min. typ. max. unit ja termal resistance junction to ambient still air 90 c/w jc termal resistance junction to case 24 c/w r ecomended crystal specifcation pericom recommends: a) gc2500003 xtal 49s/smd(4.0 mm), 25m, cl=18pf, +/-30ppm h ttp://www.pericom.com/pdf/datasheets/se/gc_gf.pdf b) fy2500081, smd 5x3.2(4p), 25m, cl=18pf, +/-30ppm h ttp://www.pericom.com/pdf/datasheets/se/fy_f9.pdf c) fl2500047, smd 3.2x2.5(4p), 25m, cl=18pf, +/-20ppm h ttp://www.pericom.com/pdf/datasheets/se/fl.pdf 11-0060
8 pi6c557-03 pci express clock www.pericom.com 04/29/1 1 ordering information (1-3) ordering code package code packagetype pi6c557-03le l pb-free & green, 16-pin tssop note: 1. t ermal characteristics and package top marking information can be found at http://www.pericom.com/packaging/ 2. e = l ead-free and green packaging 3. a dding an x sufx = tape/reel pericom semiconductor corporation ? 1 -800-435-2336 | a ll trademarks property of respective owners 1 description: 16-pin, 173-mil wide, tssop package code: l document control no. pd - 1310 revision: e date: 03/09/05 note: 1. package outline exclusive of mold flash and metal burr 2. controlling dimentions in millimeters 3. ref: jedec mo-153f/ab pericom semiconductor corporation 3545 n. 1st street, san jose, ca 95134 1-800-435-2335 ? www.pericom.com .193 .201 .047 max. .002 .006 seating plane .0256 bsc .018 .030 .004 .008 .252 bsc 1 16 .169 .177 0.05 0.15 6.4 0.45 0.75 0.09 0.20 4.3 4.5 1.20 4.9 5.1 0.65 0.19 0.30 .007 .012 packaging mechanical: 20-contact tqfn (zd) note: for latest package info, please check: http://www.pericom.com/products/packaging/mechanicals.php 11-0060
|
