1 sy88803v micrel, incm9999-051706 hbwhelp@micrel.com or (408) 955-1690 3.3v/5v 155mbps pecl low power limiting post amplifier w/ttl los sy88803v rev.: d amendment: /0 issue date: may 2006 typical applications circuit applications 155mbps sonet/sdh small form factor transceivers high-gain line driver and line receiver single 3.3v or 5v power supply up to 155mbps operation low noise pecl data outputs chatter-free ttl loss-of-signal (los) output ttl /en input programmable los level set (los lvl ) available in a tiny 10-pin msop (3mm) package features description the sy88803v low power limiting post amplifier is designed for use in fiber-optic receivers. the device connectsto typical transimpedance amplifiers (tias). the linear signal output from tias can contain significant amounts of noise and may vary in amplitude over time. the sy88803v quantizes these signals and outputs pecl level waveforms. the sy88803v operates from a single +3.3v or +5v power supply, over temperatures ranging from C40 c to +85 c. with its wide bandwidth and high gain, signals with data rates up to 155mbps and as small as 5mvp-p can beamplified to drive devices with pecl inputs. the sy88803v generates a ttl los output. a programmable loss-of-signal level set pin (los lvl ) sets the sensitivity of the input amplitude detection. los assertshigh if the input amplitude falls below the threshold set by los lvl and deasserts low otherwise. /en deasserts the true output signal without removing the input signal. typically4.6db loss-of-signal hysteresis is provided to prevent chattering. v cc v cc /en gnd gnd tocdr sy88803v 3k from transimpedance amp. d out /d out v ref v cc los lv l d in /d in 0.1 f 0.1 f 0.1 f 0.1 f los 50 2.5k 50 100 r pd r pd for 3.3v, r pd = 120 for 5v, r pd = 220 downloaded from: http:///
2 sy88803v micrel, inc.m9999-051706 hbwhelp@micrel.com or (408) 955-1690 package/ordering information pin description pin number pin name type pin function 1 /en ttl input: enable: deasserts true data output when high. default is high. 2 din data input true data input. 3 /din data input complementary data input. 4 vref reference voltage. 5 loslvl input loss-of-signal level set: a voltage between v cc and v ref on this pin sets the threshold for the data input amplitude at which los will be asserted. 6 gnd ground device ground. 7 los open-collector loss-of-signal: asserts high when the data input amplitude falls below ttl output the threshold set by los lvl . requires external pullup resistor of 2.5k . 8 /dout pecl output complementary data output. 9 dout pecl output true data output. 10 vcc power supply positive power supply. loslvl gnd 6 5 1 /en din /din vref 10 vcc dout/dout los 98 7 23 4 10-pin msop (k10-1) ordering information (1) package operating package lead part number type range marking finish sy88803vkc k10-1 commercial sy88803v sn-pb sy88803vkctr (2) k10-1 commercial sy88803v sn-pb SY88803VKG k10-1 industrial sy88803v with pb-free nipdau bar-line indicator SY88803VKGtr (2) k10-1 industrial sy88803v with pb-free nipdau bar-line indicator notes: 1. contact factory for die availability. die is guaranteed at t a = 25 c, dc electricals only. 2. tape and reel. downloaded from: http:///
3 sy88803v micrel, incm9999-051706 hbwhelp@micrel.com or (408) 955-1690 absolute maximum ratings (1) supply voltage (v cc ) ....................................... 0v to +7.0v input voltage (d in , /d in ) .........................................0 to v cc output current (i out ) continuous ............................................................. 50ma surge .................................................................... 100ma /en voltage ............................................................ 0 to v cc v ref current ......................................... C800 a to +500 a los lvl voltage ......................................................0 to v cc lead temperature (soldering, 20 sec.) ................... +260 c storage temperature (t s ) ....................... C55 c to +125 c operating ratings (2) supply voltage (v cc ) .............................. +3.0v to +3.6v or ............................................................ +4.5v to +5.5v ambient temperature (t a ), note 3 ............ C40 c to +85 c junction temperature (t j ), note 3 .......... C40 c to +120 c package thermal resistance msop ( ja ) still-air .................................................. 113 c/w ( jb ) still-air .................................................... 74 c/w v cc = 3.0v to 3.6v or 4.5v to 5.5v; r load = 50 to v cc C 2v; t a = C40 c to +85 c; typical values at v cc = 3.3v, t a = 25 c symbol parameter condition min typ max units i cc power supply current no output load 25 42 ma los lvl los lvl voltage v ref v cc v v ih /en input high voltage 2.0 v v il /en input low voltage 0.8 v i ih /en input high current v in = 2.7v 20 a v in = v cc 100 a i il /en input low current v in = 0.5v C 0.3 ma v ol los output low level i ol = +2ma 0.5 v i oh los output leakage v oh = 5.5v 250 a v oh pecl output high voltage 50 to v cc C 2v output load v cc C 1.085 v cc C 0.955 v cc C 0.880 v v ol pecl output low voltage 50 to v cc C 2v output load v cc C 1.830 v cc C 1.705 v cc C 1.555 v v offset differential output offset 100 mv v ihcmr common mode range note 5 gnd +1.7 v cc v v ref reference voltage note 6 v cc C 1.38 v cc C 1.32 v cc C 1.26 v notes: 1. permanent device damage may occur if absolute maximum ratings are exceeded. this is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. exposure to absolute maximum ratlng conditions for extended periods may affect device reliability. 2. the data sheet limits are not guaranteed if the device is operated beyond the operating ratings. 3. commercial devices are guaranteed from 0 c to +85 c ambient temperature. 4. specification for packaged product only. 5. the v ihcmr range is referenced to the most positive side of the differential input signal. 6. the current provided into or from v ref must be limited to 800 a source and 500 a sink. dc electrical characteristics (4) downloaded from: http:///
4 sy88803v micrel, inc.m9999-051706 hbwhelp@micrel.com or (408) 955-1690 v cc = 3.0v to 3.6v or 4.5v to 5.5v; r load = 50 to v cc C 2v; t a = C40 c to +85 c; typical values at v cc = 3.3v, t a = 25 c symbol parameter condition min typ max units hys los hysteresis electrical signal 2 4.6 8 db t off los release time 0.1 0.5 s t on los assert time 0.2 0.5 s t r ,t f differential output rise/fall time 1000 ps (20% to 80%) v id differential input voltage swing 5 1800 mv pp v od differential output voltage swing v id 18mvp-p 1500 mv pp v id = 5mvp-p 400 mv pp v sr los sensitivity range 5 50 mv pp a v(diff) differential voltage gain 38 db b C 3db 3db bandwidth 200 mhz s 21 single-ended small-signal gain 26 32 db note:7. specification for packaged product only. ac electrical characteristics (7) typical operating characteristics 0 10 20 30 40 50 60 70 80 90 100 0 -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 v id (mvp-p) los lvl (referenced to v cc ) (v) 3.3v los assert and deassert levels vs. los lvl 3.3vt a = 25 c 155mbpspattern 2 23 -1 0 10 20 30 40 50 60 70 80 90 100 0 -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 v id (mvp-p) los lvl (referenced to v cc ) (v) 5v los assert and deassert levels vs. los lvl 5.0vt a = 25 c 155mbpspattern 2 23 -1 downloaded from: http:///
5 sy88803v micrel, incm9999-051706 hbwhelp@micrel.com or (408) 955-1690 detailed description the sy88803v low-power limiting post-amplifier operates from a single +3.3v or +5v power supply, over temperaturesfrom C 40 c to +85 c. signals with data rates up to 155mbps and as small as 5mv pp can be amplified. figure 1 shows the allowed input voltage swing. the sy88803v generatesan los output. los lvl sets the sensitivity of the input amplitude detection.input amplifier/buffer figure 2 shows a simplified schematic of the sy88803v's input stage. the high-sensitivity of the input amplifier allowssignals as small as 5mv pp to be detected and amplified. the input amplifier allows input signals as large as1800mv pp . input signals are linearly amplified with a typically 38db differential voltage gain. since it is a limiting amplifier,the sy88803v outputs typically 1500mv pp voltage-limited waveforms for input signals that are greater than 18mv pp . applications requiring the sy88803v to operate with high-gain should have the upstream tia placed as close as possible to the sy88803v s input pins to ensure the best performance of the device.output buffer the sy88803v s pecl output buffer is designed to drive 50 lines. the output buffer requires appropriate termination for proper operation. an external 50 resistor to v cc C2v for each output pin provides this. figure 3 shows a simplifiedschematic of the output stage and includes an appropriate termination method. loss-of-signal the sy88803v generates a chatter-free ttl los. a recommended 2.5k pullup resistor to v cc is required for proper operation, as shown in figure 4. los is used todetermine that the input amplitude is too small to be considered a valid input. los asserts high if the input amplitude falls below the threshold set by los lvl and deasserts low otherwise. los can be fed back to the enable(/en) input to maintain output stability under a loss of signal condition. /en deasserts the true output signal without removing the input signals. typically 4.6db los hysteresis is provided to prevent chattering. loss-of-signal level set a programmable loss-of-signal level set pin (los lvl ) sets the threshold of the input amplitude detection. setting avoltage on los lvl between v cc and v ref sets this threshold. if desired, a resistor divider between v cc and v ref , as shown in figure 5, also creates this threshold. the smaller the voltage difference from los lvl to v cc , the smaller the los sensitivity. hence, larger input amplitude isrequired to deassert los. typical operating characteristics shows the relationship between the input amplitude detectionsensitivity and the los lvl voltage. hysteresis the sy88803v provides typically 4.6db los electrical hysteresis. by definition, a power ratio measured in db is10log(power ratio). power is calculated as v 2 in /r for an electrical signal. hence the same ratio can be stated as20log(voltage ratio). while in linear mode, the electrical voltage input changes linearly with the optical power and hence the ratios change linearly. therefore, the optical hysteresis in db is half the electrical hysteresis in db given in the datasheet. the sy88803v provides typically 2.3db los optical hysteresis. as the sy88803v is an electrical device, this datasheet refers to hysteresis in electrical terms. with 6db los hysteresis, a voltage factor of two is required to assert or deassert los. downloaded from: http:///
6 sy88803v micrel, inc.m9999-051706 hbwhelp@micrel.com or (408) 955-1690 data+ 2.5mv (min.)900mv (max.) 5mvp-p (min.)1800mvp-p (max.) data (data+) (data) v is (mvp-p) v id (mvp-p) figure 1. v is and v id definitions gnd v cc esd structure /d in d in figure 2. input structure gnd v cc /d out esd structure d out figure 3. output structure los lv l v cc r1r2 v ref figure 5. los lvl setting circuit notes. los v C 1.32v r2 r1 r2 1.32v r1 r2 2 k lvl cc =+ + + . 6 los 2.5k v cc figure 4. los output structure downloaded from: http:///
7 sy88803v micrel, incm9999-051706 hbwhelp@micrel.com or (408) 955-1690 functional block diagram layout and pcb design since the sy88803v is a high-frequency component, performance can be largely determined by the board layoutand design. a common problem with high-gain amplifiers is the feedback from the large swing outputs to the input via the power supply. design procedure the sy88803v s ground pin should be connected to the circuit board ground. use multiple pcb vias close to thepart to connect to ground. avoid long, inductive runs which can degrade performance. limiting amplifer pecl buffer gnd enable level detect /enlos d in /d in v ref v cc los lv l d out /d out downloaded from: http:///
8 sy88803v micrel, inc.m9999-051706 hbwhelp@micrel.com or (408) 955-1690 10-pin msop (k10-1) rev. 00 micrel, inc. 2180 fortune drive san jose, ca 95131 usa tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 web http://www.micrel.com the information furnished by micrel in this datasheet is believed to be accurate and reliable. however, no responsibility is assumed by micrel for its use. micrel reserves the right to change circuitry and specifications at any time without notification to the customer. micrel products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. a purchaser s use or sale of micrel products for use in life support appliances, devices or systems is at purchasers own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2006 micrel, incorporated. downloaded from: http:///
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