sy88149cl 3.3v, 1.25gbps pecl limiting post amplifier w/high gain ttl signal detect january 2009 1 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 general description the sy88149cl is a high-sensitivity limiting post amplifier designed for use in fiber-optic receivers. these devices connect 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 sy88149cl quantizes these signals and outputs pecl level waveforms. the sy88149cl operates from a single +3.3v power supply, over temperatures ranging from ?0 o c to +85 o c. with its wide bandwidth and high gain, signals with data rates up to 1.25gbps, and as small as 5mv pp , can be amplified to drive devices with pecl inputs. the sy88149cl generates a high-gain signal-detect (sd) open-collector ttl output. the sd function has a high gain input stage for increased sensitivity. a programmable signal detect level set pin (sd lvl ) sets the sensitivity of the input amplitude detection. sd asserts high if the input amplitude rises above the threshold set by sd lvl and de-asserts low otherwise. the enable input (en) de-asserts the true output signal without removing the input signal. the sd output can be fed back to the en input to maintain output stability under a loss-of-signal condition. typically, 3.4db sd hysteresis is provided to prevent chattering. all support documentation can be found on micrel? web site at: www.micrel.com . features single 3.3v power supply fast sd enable/disable time 622mbps to 1.25gbps operation low-noise pecl data outputs high-gain sd chatter-free open-collector ttl signal detect (sd) output with internal 4.75k ? pull-up resistor ttl en input programmable sd level set (sd lvl ) available in a tiny 10-pin msop package applications ge-pon/gpon/epon gigabit ethernet 1062mbps fibre channel oc-12/24 sonet/sdh high-gain line driver and line receiver low-gain tia interface markets ftth/fttp datacom/telecom optical transceiver
micrel, inc. sy88149cl january 2009 2 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 typical application circuit
micrel, inc. sy88149cl january 2009 3 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 ordering information (1) part number package type operating range package marking lead finish sy88149clkg k10-1 industrial 149c with pb-free bar line indicator nipdau pb-free sy88149clkgtr (1) k10-1 industrial 149c with pb-free bar line indicator nipdau pb-free note: 1. tape and reel. pin configuration 10-pin msop (k10-1) pin description pin number pin name type pin function 1 en ttl input: default is high. enable: this input enables the outputs when it is high. note that this input is internally connected to a 25k? pull-up resistor and will default to a logic high state if left open. 2 din data input true data input. 3 /din data input complementary data input. 4 vref reference voltage: placing a capacitor here to v cc helps stabilize sd lvl . 5 sdlvl input signal detect level set: a resistor from this pin to v cc sets the threshold for the data input amplitude at which sd will be asserted. 6 gnd ground device ground. 7 sd open-collector ttl output w/internal 4.75k? pull-up resistor signal-detect asserts high when the data input amplitude rises above the threshold set by sd lvl . 8 /dout pecl output complementary data output. 9 dout pecl output true data output. 10 vcc power supply positive power supply.
micrel, inc. sy88149cl january 2009 4 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 absolute maximum ratings (1) supply voltage (v cc ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0v to +7.0v input voltage (din, /din) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to v cc output current (i out ) continuous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ?0ma surge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ?00ma en voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to v cc v ref current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -800_a to +500_ a sd lvl voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v ref to v cc lead temperature (soldering, 20sec.) . . . . . . . . . . . . . . . . . . . . . . . 260? storage temperature (t s ) . . . . . . . . . . . . . . . . . . . . . . . . . ?5? to +150? operating ratings (2) supply voltage (v cc ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +3.0v to +3.6v ambient temperature (t a ) . . . . . . . . . . . . . . . . . . . . . ?0? to +85? junction temperature (t j ) . . . . . . . . . . . . . . . . . . . . ?0? to +125? junction thermal resistance msop ( q ja ) still-air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113?/w dc electrical characteristics v cc = 3.0 to 3.6v; r l = 50? to v cc -2v; t a = ?0? to +85?, typical values at v cc = 3.3v, t a = 25?. symbol parameter condition min typ max units i cc power supply current no output load 26 39 ma sd lvl sd lvl voltage v ref v cc v v oh pecl output high voltage v cc -1.085 v cc -0.955 v cc -0.880 v v ol pecl output low voltage v cc -1.830 v cc -1.705 v cc -1.555 v v ihcmr common mode range gnd+2.0 v cc v v ref reference voltage v cc -1.48 v cc -1.32 v cc -1.16 v ttl dc electrical characteristics v cc = 3.0 to 3.6v; r l = 50? to v cc -2v; t a = ?0? to +85?, typical values at v cc = 3.3v, t a = 25?. symbol parameter condition min typ max units 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 v in = v cc 20 100 a a i il en input low current v in = 0.5v -0.3 ma v oh sd output high level v cc > 3.3v, i oh-max < 160a v cc < 3.3v, i oh-max < 160a 2.4 2.0 v v v ol sd output low level i ol = +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 sections 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. thermal performance assumes the use of a 4-layer pcb. exposed pad must be soldered (or equivalent) to the device? most negative potential on the pcb .
micrel, inc. sy88149cl january 2009 5 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 ac electrical characteristics v cc = 3.0v to 3.6v; r load = 50? to v cc ?v; t a = ?0? to +85?. symbol parameter condition min typ max units t r , t f output rise/fall time (20% to 80%) note 4 260 ps t jitter deterministic random note 5 note 6 15 5 ps pp ps rms v id differential input voltage swing figure 1 5 1800 mv pp v od differential output voltage swing v id > 18mv pp figure 1 1500 mv pp t off sd release time 100 500 ns t on sd assert time 100 500 ns sd al low sd assert level r sdlvl = 15k?, note 8 3.4 mv pp sd dl low sd de-assert level r sdlvl = 15k?, note 8 2.3 mv pp hys l low sd hysteresis r sdlvl = 15k?, note 7 3.4 db sd am medium sd assert level r sdlvl = 5k?, note 8 6.2 8 mv pp sd dm medium sd de-assert level r sdlvl = 5k?, note 8 3 4.2 mv pp hys m medium sd hysteresis r sdlvl = 5k?, note 7 2 3.4 5 db sd ah high sd assert level r sdlvl = 100?, note 8 16.4 20 mv pp sd dh high sd de-assert level r sdlvl = 100?, note 8 8 10.8 mv pp hys h high sd hysteresis r sdlvl = 100?, note 7 2 3.4 5 db b -3db 3db bandwidth 1 ghz a v(diff) differential voltage gain 42 db s 21 single-ended small-signal gain 36 db notes: 4. amplifier in limiting mode. input is a 200mhz square wave. 5. deterministic jitter measured using 1.25gbps k28.5 pattern, v id = 10mv pp . 6. random jitter measured using 1.25gbps k28.7 pattern, v id = 10mv pp . 7. this specification defines electrical hysteresis as 20log(sd assert/sd de-assert). the ratio 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 hysteresis range 2db-5db, shown in the ac characteristics table, will be 1db-4db optical hysteresis. 8. see ?ypical operating characteristics?for a graph showing how to choose a particular r sdlvl for a particular sd assert and its associated de-assert amplitude.
micrel, inc. sy88149cl january 2009 6 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 typical operating characteristics v cc = 3.3v, t a = 25?, r l = 50? to v cc ?v, unless otherwise stated. r sdlvl (k?) r sdlvl (k?)
micrel, inc. sy88149cl january 2009 7 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 functional block diagram detailed description the sy88149cl high-sensitivity limiting post amplifier operates from a single +3.3v power supply, over temperatures from ?0? to +85?. signals with data rates up to 1.25gbps and as small as 5mv pp can be amplified. figure 1 shows the allowed input voltage swing. the sy88149cl generates an sd output, allowing feedback to en for output stability. sd lvl sets the sensitivity of the input amplitude detection. input amplifier/buffer figure 2 shows a simplified schematic of the input stage. the high-sensitivity of the input amplifier allows signals as small as 5mv pp to be detected and amplified. the input amplifier allows input signals as large as 1800mv pp . input signals are linearly amplified with a typically 42db differential voltage gain. since it is a limiting amplifier, the sy88149cl outputs typically 1500mv pp voltage-limited waveforms for input signals that are greater than 12mv pp . applications requiring the sy88149cl to operate with high-gain should have the upstream tia placed as close as possible to the sy88149cl? input pins. this ensures the best performance of the device. output buffer the sy88149cl? 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 ?v for each output pin provides this. figure 3 shows a simplified schematic of the output stage. signal detect the sy88149cl generates a chatter-free signal-detect (sd) open-collector ttl output with internal 4.75k? pull- up resistor, as shown in figure 4. sd is used to determine that the input amplitude is too small to be considered a valid input. sd asserts high if the input amplitude rises above threshold set by sdlvl and de- asserts low otherwise. sd can be fed back to the enable (en) input to maintain output stability under a sds of signal condition. en de-asserts low the true output signal without removing the input signals. typically, 3.4db sd hysteresis is provided to prevent chattering. signal detect level set a programmable sd level set pin (sd lvl ) sets the threshold of the input amplitude detection. connecting an external resistor between v cc and sd lvl sets the voltage at sd lvl . this voltage ranges from v cc to v ref . the external resistor creates a voltage divider between v cc and v ref , as shown in figure 5. hysteresis the sy88149cl provides typically 3.4db sd electrical hysteresis. by definition, a power ratio measured 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 hence the ratios change linearly. therefore, the optical hysteresis in db is half the electrical hysteresis in db given in the data sheet. the sy88149cl is an electrical device; this data sheet refers to hysteresis in electrical terms. with 3.4db sd hysteresis, a voltage factor of 1.5 is required to assert or de-assert sd.
micrel, inc. sy88149cl january 2009 8 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 figure 1. vis and vid definition figure 2. input structure figure 3. output structure figure 4. sd output structure figure 5. sd lvl setting circuit note: recommended value for r sdlvl is 15k? or less.
micrel, inc. sy88149cl january 2009 9 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 related product and support documentation part number function data sheet link sy88933al 3.3v/5v 1.25gbps pecl high-sensitivity limiting post amplifier with ttl sd http://www.micrel.com/product-info/sy88933al.shtml application notes notes on sensitivity and hysteresis in micrel post amplifiers http://www.micrel.com/product-info/app_hints+notes.shtml
micrel, inc. sy88149cl january 2009 10 m9999-011609-c hbwhelp@micrel.com or (408) 955-1690 package information 10-pin msop (k10-1) 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 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? use or sale of micrel products for use in life support appliances, devices or systems is a purchaser? own risk and purchaser agrees to fully indemnify micrel for any damages resulting from such use or sale. ?2005 micrel, incorporated.
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