gennum corporation p.o. box 489, stn. a, burlington, ontario, canada l7r 3y3 tel. +1 (905) 632-2996 fax. +1 (905) 632-5946 e-mail: info@gennum.com www.gennum.com revision date: june 2004 document no. 521 - 68 - 05 data sheet gs9028 features ? smpte 259m compliant two complementary outputs, adjustable from 50 to 1000mvp-p into 75 ? loads operational from dc to 622mb/s nominal 470ps rise and fall times < 7% output amplitude control 45% system power reduction over the gs9008 no external pulldown resistors required input hysteresis operational down to 80mv input amplitude operates from a single +5 or -5 volt supply 8 pin soic pb-free and green applications 4?sc, 4:2:2, and 4:4:4:4 serial digital video interfaces from 143mb/s to 540mb/s; general purpose high speed cable driver applications. description the gs9028 is a second generation bipolar integrated circuit designed to drive two 75 ? co-axial cables. the gs9028 features two complementary outputs whose amplitude is controlled within 7%. the output signal levels are also adjustable from as low as 50mv to as high as 1000mv with little change in other performance parameters. the output amplitud e of the output st age is varied by adjusting the r set resistor value. the gs9028 consumes 45% less system power than the gs9008 and does not require external pulldown resistors resulting in a smaller pcb foot print. operational with input amplitudes as low as 80mv, t he gs9028 is a robust serial interface device. the gs9028 is packaged in an 8 pin soic and operates from a single +5 or -5 volt supply. ordering information part number pac k ag e temperature pb-free and green gs9028-cka 8 pin soic 0c to 70c no gs9028-cta 8 pin soic tape 0c to 70c no gs9028-ckae3 8 pin soic 0c to 70c yes GS9028-CTAE3 8 pin soic tape 0c to 70c yes sdo r set sdo sdi sdi bandgap reference and biasing circuit output stage & rise/fall time control circuit input differential pair with hysteresis block diagram genlinx ? ii gs9028 cable driver with two adjustable outputs
absolute maximum ratings t a = 25c unless otherwise specified pa r a m e t e r value supply voltage 5.5v input voltage range (any input) -0.3 to (v cc +0.3)v operating temperature range 0 to 70c storage temperature -65 to 150c lead temperature (soldering, 10 sec) 260c dc electrical characteristics v cc = 5v, t a = 0c to 70c unless otherwise shown. specifications assume 800mv output amplitude levels into end terminated 75 ? transmission lines. pa r a m e t e r symbol conditions min typ max units notes test level supply voltage v cc 4.75 5.00 5.25 v 1 system power consumption p d driving two 75 ? cables - 165 195 mw 3 supply current s - 33 39 ma 3 common mode input voltage range v cm,in 2.4+(v diff /2) - v cc -(v diff /2) v 2 differential input v diff 80 - 1000 mv 2 common mode output voltage range v cm,out - v cc -v out - v 2 differential output v out r set = 59 ? 750 800 850 mv 1 input hysteresis 10 - - mv 2 ac electrical characteristics v cc = 5v, t a = 0c to 70c unless otherwise shown. specifications assume 800mv output amplitude levels into end terminated 75 ? transmission lines. pa r a m e t e r symbol conditions min typ max units notes test level serial data rate 0 - 622 mb/s 1 additive jitter 270mb/s - 25 - ps p-p 1 2 540mb/s - 25 - 622mb/s - 50 - output rise/fall time t r , t f 20% - 80% 400 470 700 ps 3 mismatch in output rise/fall times - 50 100 ps 1 overshoot - 5 8 % 1 duty cycle distortion - 50 100 ps 2 output return loss 540mhz - 17 - db 2 test levels 1. 100% tested at 25c. 2. guaranteed by design. 3. correlated value. notes 1. rms additive jitter measured using pseudo random bit sequence (2 23 - 1). 2. measured with gennum evaluation board (eb-rd35). 521 - 68 - 05 2 of 7 gs9028
521 - 68 - 05 3 of 7 gs9028 pin connections sdo sdo v ee r set v cc sdi sdi v ee gs9028 top view 1 2 3 4 8 7 6 5 pin descriptions number symbol type description 1 sdo o serial data output (inverse). 2 sdo o serial data output. 4 r set i output amplitude control resistor. 6 sdi i serial data input (inverse). 7 sdi i serial data input. input/output circuits sdi sdi v cc fig. 1 input circuit (pins 6 and 7) r set sdo sdo + - fig. 2 output circuit (pins 1 and 2)
521 - 68 - 05 4 of 7 gs9028 typical performace curves (measured using the typical application circuit) fig. 3 output eye diagram 270mb/s fig. 5 output eye diagram 622mb/s fig. 4 output eye diagram 540mb/s
521 - 68 - 05 5 of 7 gs9028 detailed description input interfacing sdi/ sdi are high impedance differential inputs. two conditions must be observed when interfacing to these inputs: 1. the input signal amplitude must be between 80mv and 1000mv. 2. the common mode voltage r ange must be as specified in the dc characteristics table (page 2). for 800mv input amplitude signals, this corresponds to a common mode voltage range between 2.8 and 4.6 volts. figures 6 and 7 illustrate two methods of interfacing the gs9028 to the gennum gs9024 (cable equalizer), gs9035 (reclocker) or the gs9025 (receiver). figure 6 illustrates the simplest interface and is recommended when the trace lengths between the driver and the gs9028 are less than 0.5in. the pull up resistors should be placed near the gs9028 to serve as end terminations. gs9024 or gs9035 or gs9025 gs9028 75 ? 75 ? 10nf v cc + _ + _ fig. 6 when trace lengths become longer than 0.5in and data rates greater than 360mb/s, electromagnetic reflections begin to affect signal integr ity. to minimize reflections, controlled impedance trac es and source and end terminations should be used as shown in figure 7. although terminations on both sides reduce the signal swing by a factor of two, the gs9028 is designed to meet this need with ultra low input amplitude requirements (as low as 80mv). this low input amplitude requirement also allows the use of 50 ? transmission lines (which are more robust and easier to control in multilayer boards) to interconnect the gs9024/25/35 an d the gs9028. gs9024 or gs9035 or gs9025 gs9028 + _ + _ v cc 75 ? 100nf 10nf 75 ? 75 ? 75 ? fig. 7 the gs9028 can also be configured to accept ac coupled input signals. in this case, the inputs must be dc biased as illustrated in figure 8. r1 r1 10nf 1f 1f r2 r2 v cc gs9028 + _ fig. 8 the recommended values for r1 and r2 are: r1 = 1.35z o r2 = 3.85z o where z o is the transmission line characteristic impedance. for 75 ? cable, r1 = 100 ? and r2 = 287 ? . output interfacing figure 9 illustrates the recommended interface for ac coupled outputs. r t gs9028 r r t = r = z o gs9028 r l l r t v cc + _ 10nf 1f 1f fig. 9
521 - 68 - 05 6 of 7 gs9028 the termination resistor (r t ) value should be equal to the characteristic impedance of the cable. controlled impedance traces should be us ed for the outputs and the termination resistors should be placed near the gs9028. the inductor (l) and resistor (r) are used to optimize the output return loss and are pcb dependent. typically, r equals the transmission line characteristic impedance and l is approximately 8.2nh. output amplitude adjustment the gs9028 outputs are adjustable from as low as 50mv to as high as 1000mv. the output amplitude is set by the r set resistor connected to pin 4. the relationship between the output amplitude (v out ) and r set is approximately given by the equation below: r set = (1.3696 x z o )/(2 x v out ) - 5.5 where z o is in ohms and v out is in volts. the minimum value of r set is 46 ? . for 75 ? cable and 800mv output amplitudes, the value of r set is 59 ? . also, note that the above formula assumes that the transmission line is properly end terminated. typical application circuit 75 75 75 75 59 10n 8.2nh 1 1 1 100n v cc r set v ee sdo sdo v ee sdi sdi v cc v cc 8.2nh gs9028 4 3 2 1 5 6 7 8 all resistors in ohms, all capacitors in farads, unless otherwise shown.
521 - 68 - 05 7 of 7 gennum corporation mailing address: p.o. box 489, stn. a, burlington, ontario, canada l7r 3y3 tel. +1 (905) 632-2996 fax. +1 (905) 632-5946 shipping address: 970 fraser drive, burlington, ontario, canada l7l 5p5 gennum japan corporation shinjuku green tower building 27f 6-14-1, nishi shinjuku shinjuku-ku, tokyo 160-0023 japan tel: +81 (03) 3349-5501 fax: +81 (03) 3349-5505 gennum uk limited centaur house, ancells bus. park, ancel ls rd, fleet, hants, england gu13 8uj tel. +44 (0)1252 761 039 fax +44 (0)1252 761 114 gennum corporation assumes no responsibility for the use of any circuits described herein and makes no representations that th ey are free from patent infringement. ? copyright april 1996 gennum corporation. all rights reserved. printed in canada. gs9028 package dimensions 0.49 max 3.81 0.05 3 spaces @ 1.27 0.05 4.0 max 6.20 max 0.25 max 1 8 1.91 max 4 5 1.27 max 0.25 max 5.00 max. 0.60 max = = = 8 pin soic revision notes: added lead-free and green information. caution electrostatic sensitive devices do not open packages or handle except at a static-free workstation document identification data sheet the product is in production. gennum reserves the right to make changes at any time to improve reliability, function or design, in order to provide the best product possible.
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