sy88289al 3.3v, 3.2gbps cml low - power limiting post amplifier with ttl loss - of - signal micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 (408) 944 - 0800 ? fax + 1 (408) 474 - 1000 ? http://www.micrel.com february 2007 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 general description the sy88289al low - power limiting post amplifier is designed for use in fiber - optic receivers. the device connects to typical transimpedance amplifiers (tias). the linear signal output from tias can contain significant amounts of noise and may vary in amplitude over time. the sy88289al quantizes these signals and outputs cml - level waveforms. the sy88289al operates from a single +3.3v power supply, over temperatures ranging from ? 40 o c to +85 o c. with its wide bandwidth and high gain, sign als with data rates up to 3.2gbps, and as small as 10mv p-p , can be amplified to drive devices with cml inputs or ac - coupled cml/pecl inputs. the sy88289al generates a loss - of - signal (los) open - collector ttl output. a programmable loss - of - signal level - set p in (los lvl ) sets the sensitivity of the input amplitude detection. los asserts high if the input amplitude falls below the threshold set by los lvl and de- asserts low otherwise. the enable bar input (/en) de- asserts the true output signal without removing t he input signal. the los output can be fed back to the /en input to maintain output stability under a loss - of - signal condition. typically, 3.5db los hysteresis is provided to prevent chattering. all support documentation can be found on micrel?s web site a t www.micrel.com . features ? single 3.3v power supply ? 125mbps to 3.2gbps operation ? low - noise cml data outputs ? chatter - free open - collector ttl loss - of - signal (los) output with internal 4.75k ? pull - up resistor ? ttl /en input ? internal 50 ? input termination ? programmable los level set (los lvl ) ? ideal for multi - rate applications ? available in a tiny 3mmx3mm 16 - pin qfn package applications ? apon, bpon, epon, gepon, and gpon ? gigabit ethernet ? fibre chan nel ? sonet/sdh:oc - 3/12/24/48 ? stm 1/4/8/16 ? high - gain line driver and line receiver markets ? optical transceivers ? datacom/telecom typical application
micrel, inc. sy88289al february 2007 2 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 ordering information part number package type operating range package marking lead finish sy88289alm g qfn -16 industrial 289a with pb - free bar line indicator nipdau pb - free sy88289almgtr (1) qfn -16 industrial 289a with pb - free bar line indicator nipdau pb - free note: 1. tape and reel. pin configuration 16- pin qfn pin description pin number pin na me type pin function 1, 12 vcc power supply positive power supply. 2 din data input true data input. 3 /din data input complementary data input. 4, 9 gnd ground device ground. 5 vref reference voltage: placing a capacitor here to vcc helps stabilize los lvl . 6 loslvl input loss -of - signal level set: a resistor from this pin to v cc sets the threshold for the data input amplitude at which los will be asserted. 7, 14, 15, 16 n/c no connect. 8 los open - collector ttl output w/internal 4.75k ? pull - up resistor loss -of - signal: asserts high when the data input amplitude rises below the threshold sets by los lvl . 10 /dout cml output complementary data output. 11 dout cml output true data output. 13 /en ttl input: default is high. /enable: this input enables the outputs when it is low. note that this input is internally connected to a 25k ? pull - up resistor and will default to a logic high state if left open.
micrel, inc. sy88289al february 2007 3 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 absolute maximum ratings (1) supply voltage (v cc ) .................................... 0v to +4.0v input voltage (din, /din ) ................................... 0 to v cc output current (i out ) ............................................ + 25ma /en voltage ........................................................ 0 to v cc v ref current??????????? - 800ua to + 500ua los lvl voltage .............................................. v ref to v cc lead temperature (soldering, 20sec.) .................. 260c storage temperature (t s ) ..................... - 65c to +150c operating ratings (2) supply voltage (v cc ) .............................. +3 .0v to +3.6v ambient temperature (t a ) .................... ? 40c to +85c junction temperature (t j ) .................. ? 40c to +125c junction thermal resistance qfn ( ja ) still - air ..................................................... 60c/w qfn ( jb ) junction - to - board ..................................... 38 o c/w dc electrical characteristics v cc = 3.0v to 3.6v; r l = 50 ? to v cc ; t a = ? 40c to +85c. symbol parameter condition min typ max units i cc power supply current no output load 42 65 ma los lvl los lvl voltage v ref v cc v v oh cml output high voltage v cc - 0.020 v cc - 0.005 v cc v v ol cml output low voltage vcc =3.3v v cc - 0.475 v cc - 0.400 v cc - 0.350 v v offset differential output offset 80 mv z o single - ended output impedance 40 50 60 ? z i single - ended input impedance 40 50 60 ? v ref reference voltage v cc - 1.28 v ttl dc electrical characteristics v cc = 3.0v to 3.6v; r l = 50 ? to v cc ; t a = ? 40c to +85c. symbol parameter condition min typ max units v ih /en input high voltage 2.0 v il /en input low voltage 0.8 v i ih /en input high current v in = 2.7v v in = v cc 20 100 ua ua i il /en input low current v in = 0.5v -300 ua v oh los output high level v cc > 3.3v, i oh - max < 160ua v cc < 3.3v, i oh - max < 160ua 2.4 2.0 v v v ol los out put low level sinking 2ma 0.5 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 section s of this data sheet. exposure to absolute maximum rating 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. package thermal resistance assum es exposed pad is soldered (or equivalent) to the device?s most negative potential (gnd) on the pcb. jb uses 4 - layer ( ja ) in still - air number, unless otherwise stated.
micrel, inc. sy88289al february 2007 4 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 ac electrical characteristics v cc = 3.0v to 3.6v; r l = 50 ? to v cc ; t a = ? 40c to +85c. symbol parameter condition min typ max units t r , t f output rise/fall time (20% to 80%) note 4 6 0 120 ps t jitter deterministic random note 5 note 6 15 5 ps pp ps rms v id differential input voltage swing figure 1 10 1800 mv pp v od differential output voltage swing v id > 18mv pp , figure 1 700 800 950 mv pp t off los release time 2 10 s t on los ass ert time 2 10 s los al low los assert level r loslvl = 15k ?, note 8 7.8 mv pp los dl low los de - assert level r loslvl = 15k ?, note 8 12 mv pp hys l low los hysteresis r loslvl = 15k ?, note 7 3.7 db los am medium los assert level r loslvl = 5k ?, note 8 1 0 17 mv pp los dm medium los de - assert level r loslvl = 5k ?, note 8 25 40 mv pp hys m medium los hysteresis r loslvl = 5k ?, note 7 2 3.3 4.5 db los ah high los assert level r loslvl = 100 ?, note 8 30 45 mv pp los dh high los de - assert level r loslvl = 100 ?, no te 8 69 95 mv pp hys h high los hysteresis r loslvl = 100 ?, note 7 2 3.7 4.5 db b - 3db 3db bandwidth 2 ghz a v(diff) differential voltage gain 32 38 db s 21 single - ended small - signal gain 26 32 db notes: 4. amplifier in limiting mode. input is a 200 mhz square wave. 5. deterministic jitter measured using 3.2gbps k28.5 pattern, v id = 10mv pp . 6. random jitter measured using 3.2gbps k28.7 pattern, v id = 10mv pp . 7. this specification defines electrical hysteresis as 20log (los de - assert/los assert). the r atio between optical hysteresis and electrical hysteresis is found to vary between 1.5 and 2, depending upon the level of received optical power and rosa characteristics. based upon that ratio, the optical hysteresis corresponding to the electrical hystere sis range 2db - 4.5 db, shown in the ac characteristics table, will be 1db - 3db. 8. see ?typical operating characteristics? for a graph showing how to choose a particular r loslvl for a particular los assert and its associated de - assert amplitude.
micrel, inc. sy88289al february 2007 5 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 typical operating characteristics
micrel, inc. sy88289al february 2007 6 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 functional block diagram detailed description the sy88289al low - power limiting post amplifier operates from a single +3.3v power supply, over temperatures from ? 40 o c to +85 o c. signals with data rates of up to 3.2gbps and as small as 10mv pp can be amplified. figure 1 shows the allowed input voltage swing. the sy88289al generates a los output. los lvl sets the sensitivity of the input amplitude detection. input amp lifier/buffer figure 2 shows a simplified schematic of the sy88289al?s input stage. the high - sensitivity of the input amplifier allows signals as small as 10mv pp to be detected and amplified. the input amplifier also allows input signals as large as 1800mv pp . input signals are linearly amplified with a typical 38db differential voltage gain. since it is a limiting amplifier, the sy88289al outputs typically 800mv pp voltage - limited waveforms for input signals that are greater than 12mv pp . applications requiri ng the sy88289al to operate with high gain should have the upstream tia placed as close as possible to the sy88289al?s input pins to ensure the best performance of the device. output buffer the sy88289al?s cml output buffer is d esigned to drive 50 ? lines. the output buffer requires appropriate termination for proper operation. an external 50 ? resistor to v cc for each output pin provides this. figure 3 shows a simplified schematic of the output stage. loss - of - signal the sy88289a l generates a chatter - free los open - collector ttl output with an internal 4.75k ? pull - up resistor as shown in figure 4. los is used to determine that the input amplitude is large enough to be considered a valid input. los asserts high if the input amplitud e falls below the threshold sets by los lvl and de - asserts low otherwise. los can be fed back to the enable bar (/en) input to maintain output stability under a loss of signal condition. /en de - asserts the true output signal without removing the input signa ls. typically, 3.5db los hysteresis is provided to prevent chattering. loss - of - signal level set a programmable los level - set (los lvl ) pin sets the threshold of the input amplitude detection. connecting an external resistor between v cc and los lvl sets the v oltage at los lvl . this voltage ranges from v ref to v cc . the external resistor creates a voltage divider between v cc and v ref as shown in figure 5. hysteresis the sy88289al provides typically 3.5db los electrical hysteresis. by definition, a power ratio mea sured in db is 10log (power ratio). power is calculated as v 2 in /r for an electrical signal. hence, the same ratio can be stated as 20log (voltage ratio). while in linear mode, the electrical voltage input changes linearly with the optical power and therefo re, the ratios change linearly. thus, the optical hysteresis in db is half the electrical hysteresis in db given in the data sheet. since the sy88289al is an electrical device, this data sheet refers to hysteresis in electrical terms. with 3.5db los hyster esis, a voltage factor of 1.5 is required to assert or de - assert los.
micrel, inc. sy88289al february 2007 7 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 figure 1. v is and v id definition figure 2. input structure figure 3. output structure figure 4. input structure figu re 5. los lvl setting circuit
micrel, inc. sy88289al february 2007 8 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 package information 16- pin (3mm x3mm) qfn
micrel, inc. sy88289al february 2007 9 m9999 - 021207-b hbwhelp@micrel.com or (408) 955 - 1690 pcb thermal consideration for 16 - pin qfn package package notes: 1. package meets level 2 qualification. 2. all parts are dry - packaged before shipment. 3. exposed pad must be soldered t o a ground for proper thermal management. 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 data sheet 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 mal function of a product can reasonably be expected to result in personal injury. life support devices or systems a re 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 res ult in a significant injury to the user. a purchaser?s use or sale of micrel produc ts for use in life support appliances, devices or systems is a purchaser?s own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ? 2006 micrel, incorporated.
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