sy88147dl 3.3v, 1.25gbps pecl limiting post amplifier w/high gain ttl loss-of-signal february 2007 1 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 general description the sy88147dl 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 sy88147dl quantizes these signals and outputs pecl level waveforms. the sy88147dl 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, signals with data rates up to 1.25gbps, and as small as 5mv pp , can be amplified to drive devices with pecl inputs. the sy88147dl generates a high-gain loss-of-signal (los) open-collector ttl output. the los function has a high gain input stage for increased sensitivity. a programmable loss-of-signal level set pin (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 the 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 at: www.micrel.com . features ? single 3.3v power supply ? dc to 1.25gbps operation ? low-noise pecl data outputs ? high-gain los ? chatter-free open-collector ttl loss of signal (los) output with internal 4.75k ? pull-up resistor ? ttl /en input ? programmable los level set (los lvl ) ? available in a tiny 10-pin msop applications ? apon/bpon/epon/gepon/gpon ? gigabit ethernet ? 531mbps and 1062mbps fibre channel ? oc-3 and oc-12/24 sonet/sdh ? high-gain line driver and line receiver ? low-gain tia interface markets ? ftth ? datacom/telecom ? optical transceiver
micrel, inc. sy88147dl february 2007 2 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 typical application circuit
micrel, inc. sy88147dl february 2007 3 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 ordering information part number package type operating range package marking lead finish sy88147dlkg k10-1 industrial 147d with pb-free bar line indicator nipdau pb-free sy88147dlkgtr (1) k10-1 industrial 147d 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 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. 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 los lvl . 5 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. 6 gnd, exposed pad ground device ground. 7 los open-collector ttl output w/internal 4.75k ? pull-up resistor loss-of-signal: asserts high when the data input amplitude falls below the threshold sets by los lvl . 8 /dout pecl output complementary data output. 9 dout pecl output true data output. 10 vcc power supply positive power supply.
micrel, inc. sy88147dl february 2007 4 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 ) continuou s........................................................ 50ma surge .............................................................. 100ma /en voltage ............................................................0 to v cc v ref current .......................................... -800 a to +500a los lvl voltage................................................. v ref to v cc lead temperature (solderi ng, 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 msop ( ja ) still-air .......................................... 113 c/w dc electrical characteristics v cc = 3.0 to 3.6v; r l = 50 ? to v cc ?2v; t a = ?40c to +85c, typical values at v cc = 3.3v, t a = 25c. symbol parameter condition min typ max units i cc power supply current no output load 26 39 ma los lvl los 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 -1.850 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 = ?40c to +85c, typical values at v cc = 3.3v, t a = 25c. 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 los output high level v cc > 3.3v, i oh-max < 160 a v cc < 3.3v, i oh-max < 160 a 2.4 2.0 v v v ol los 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 oper ation is not implied at conditions other than those detailed in the operational sections of this data sheet. exposure to absolute maximum ra ting 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. ex posed pad must be soldered (or equivalent) to the device?s most neg ative potential on the pcb.
micrel, inc. sy88147dl february 2007 5 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 ac electrical characteristics v cc = 3.0v to 3.6v; r load =50 to v cc ?2v; t a = ?40c to +85c. symbol parameter condition min typ max units t r , t f output rise/fall time (20% to 80%) note 4 260 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 los release time 2 10 s t on los assert time 2 10 s los al low los assert level r loslvl = 15k ? , note 8 2.3 mv pp los dl low los de-assert level r loslvl = 15k ? , note 8 3.4 mv pp hys l low los hysteresis r loslvl = 15k ? , note 7 3.4 db los am medium los assert level r loslvl = 5k ? , note 8 4.2 mv pp los dm medium los de-assert level r loslvl = 5k ? , note 8 6.2 mv pp hys m medium los hysteresis r loslvl = 5k ? , note 7 2 3.4 4.5 db los ah high los assert level r loslvl = 100 ? , note 8 10.8 mv pp los dh high los de-assert level r loslvl = 100 ? , note 8 16.4 mv pp hys h high los hysteresis r loslvl = 100 ? , note 7 2 3.6 4.5 db b -3db 3db bandwidth 1 ghz a v(diff) differential voltage gain 42 db s 21 single-ended small-signal gain 30 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 el ectrical hysteresis as 20log (los de-assert/los assert). the ratio between optical hysteresis a nd electrical hysteresis is found to vary between 1.5 and 2 depending on the leve l of received optical power and rosa characteristics. based on that ratio, the optical hysteresis corresponding to the el ectrical hysteresis range 2db-4.5db, show n in the ac characteristics table, will be 1db-3db. 8. see ?typical operating characteristics? fo r a graph showing how to choose a particular r loslvl for a particular los assert and its associated de-assert amplitude.
micrel, inc. sy88147dl february 2007 6 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 typical operating characteristics v cc = 3.3v, t a = 25c, r l = 50 ? to v cc ?2v, unless otherwise stated.
micrel, inc. sy88147dl february 2007 7 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 functional block diagram detailed description the sy88147dl high-sensitivity limiting post amplifier operates from a single +3 .3v power supply, over temperatures from ?40c to +85c. 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 sy88147dl generates a los output, allowing feedback to /en for output stability. los lvl sets the sensitivity of the i nput 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 sy 88147dl outputs typically 1500mv pp voltage-limited waveforms for input signals that are greater than 12mv pp . applications requiring the sy88147dl to operate with high-gain should have the upstream tia placed as close as possible to the sy88147dl?s input pins to ensure the best performance of the device. output buffer the sy88147dl?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 ?2v for each output pin provides this. figure 3 shows a simplified schematic of the output stage. loss-of-signal the sy88147dl generates a chatter-free loss-of-signal (los) open-collector ttl output with internal 4.75k ? pull-up resistor as shown in figure 4. los is used to determine that the input amplitude is too small to be considered a valid input. los asserts high if the input amplitude falls below the threshold sets by loslvl and de-asserts low otherwise. los can be fed back to the enable (/en) input to maintain output stability under a loss of signal condition. /en de-asserts low the true output signal without remo ving the input signals. typically, 3.5db los hysteresis is provided to prevent chattering. loss-of-signal-level set a programmable los level set pin (los lvl ) sets the threshold of the input am plitude detection. connecting an external resistor between v cc and los lvl sets the voltage at los 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 sy88147dl typically provides 3.5db los 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 sy88147dl is an electrical device; this data sheet refers to hysteresis in electrical terms. with 3.5db los hysteresis, a voltage factor of 1.5 is required to assert or de-assert los.
micrel, inc. sy88147dl february 2007 8 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. los output structure figure 5. los lvl setting circuit note: recommended value for rloslvl is 15k ? or less.
micrel, inc. sy88147dl february 2007 9 m9999-021207-b hbwhelp@micrel.com or (408) 955-1690 related product and su pport documentation part number function data sheet link sy88903al 3.3v/5v 1.25gbps pecl high-sensitivity limiting post amplifier with ttl los http://www.micrel.com/product-info/sy88903al.shtml application notes notes on sensitivity and hysteresis in micrel post amplifiers http://www.micrel.com/produc t-info/app_hints+notes.shtml
micrel, inc. sy88147dl february 2007 10 m9999-021207-b 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 belie ved to be accurate and reliable. however, no responsibility is a ssumed by micrel for its use. micrel reserves the right to change circuitry and specificati ons at any time without notification to the customer. micrel products are not designed or authori zed for use as components in life support app liances, devices or systems where malfu nction of a product can reasonably be expected to result in personal injury. li fe 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 resul t in a significant injury to the user. a purchaser?s use or sale of micrel products for use in life s upport appliances, devices or systems is a pu rchaser?s own risk and purchaser agrees to fully indemnify micrel fo r any damages resulting from such use or sale. ? 2005 micrel, incorporated.
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