3.3V, 2.7Gbps SDH/SONET Micrel, Inc. SY88952L SY88952L LASER DRIVER WITH AUTOMATIC POWER CONTROL FEATURES DESCRIPTION Single 3.3V power supply SY88952L is a highly integrated and programmable laser driver for SONET/SDH application up to 2.7Gbps. Up to 2.7Gbps operation The device accepts differential PECL or LVDS data and Rise/Fall times: < 75ps clock inputs. It provides programmable bias and Independent programmable laser modulation and modulation currents for driving a laser. The modulation bias currents output of SY88952L can be DC-coupled to drive the laser Bias current to 100mA and modulation current to diode, providing a significant power saving over AC- 90mA coupled operation. A synchronizing TTL input latch can be used to reduce jitter if a clock signal is available. A Automatic average laser power control TTL enable is also incorporated in the device. EN only Bias and modulation current monitors enables/disables I . It does not enable/disable I . MOD BIAS Operating temperature range of 40C to +85C An automatic power controller (APC) is integrated into Complies with ANSI, ITU, and Bellcore SDH/SONET SY88952L to maintain a constant average optical output specifications power over temperature and lifetime. The modulation Available in DIE form and 32-pin (5mm 5mm) current can be externally temperature compensated to EPAD-MLF package minimize the variation of extinction ratio of the optical output. Several safety features will enable an alarm function APPLICATIONS when the output signal is too high, or bias current is too high. OC-48 transceivers and transponders There are two alarm conditions: SONET/SDH transmission system 1. /FAIL asserts when bias current loop goes to Add drop mux maximum of it s range. I and I still flow under BIAS MOD Metro area network this condition. 2.5Gbps optical transmitter 2. /FAIL asserts when I or I are too BIASMAX MODSET high (implying I or I will be too high). All currents Fiber optical module BIAS MOD will shut off under this condition. MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc. Rev.: B Amendment: /0 M9999-082205 1 Issue Date: August 2005 hbwhelp micrel.com or (408) 955-1690SY88952L Micrel, Inc. PACKAGE/ORDERING INFORMATION (1) Ordering Information Package Operating Package Lead Part Number Type Range Marking Finish 32 31 30 29 28 27 26 25 SY88952LMI MLF-32 Industrial SY88952L Sn-Pb VCC 1 24 VCC 23 (2) D 2 /Q SY88952LMITR MLF-32 Industrial SY88952L Sn-Pb /D 3 22 /Q SY88952LMG MLF-32 Industrial SY88952L with Pb-Free 4 21 VCC VCC 5 20 Q CLK Pb-Free bar-line indicator NiPdAu /CLK 6 19 Q (2) SY88952LMGTR MLF-32 Industrial SY88952L with Pb-Free 7 18 VCC VCC Pb-Free bar-line indicator NiPdAu 8 17 VEE LATCH 910 111213141516 Notes: 1. Dice are designed to operate from 40C to +85C, but are tested and guaranteed to T = +25C A only. 2. Tape and Reel. 32-Pin MLF (MLF-32) PIN DESCRIPTION Pin Number Pin Name Pin Function 16 BIAS Bias Current Output (I ). BIAS 11 BIASMON Bias Current Monitor: Sinks current that is proportional to I , (I /40). An external current BIAS BIAS path must exist to V . CC 31 BIASMAX A resistor (R ) connected to ground sets the maximum bias current. BIASMAX See Typical Operating Characteristics (I vs. R ). BIAS BIASMAX 26 SLOW Connect a capacitor (C ) to ground to provide a slow-start. SLOW 5, 6 CLK,/CLK Differential Clock Input. 75K pull-down on CLK, 75k pull-up and 75k pull-down on /CLK. 2, 3 D, /D Differential Data Input. 75K pull-down on D, 75k pull-up and 75k pull-down on /D. 9 EN TTL Input with 75k pull-up: Default HIGH for normal operation LOW to disable modulation current. 8 LATCH TTL Input with 75k pull-up: Default HIGH for latched (clocked) data LOW for direct data. 25 MD Connect this pin to a monitor photodiode anode, a resistor (R ) and a capacitor (C ). APCSET APCSET This sets the desired average optical power. 19, 20, 22, 23 Q, /Q Differential Output: Modulation current output (I ). MOD 12 MODMON Modulation Current Monitor: Sinks current that is proportional to I , (I /45). An external MOD MOD current path must exist to V . CC 30 MODSET A resistor (R ) connected to ground sets the modulation current. MODSET See Typical Operating Characteristics (I vs. R ). MODSET MOD 13 /FAIL TTL Open-Collector Output: Connect a 5k resistor to V . Indicates APC failure when LOW. CC 1, 4, 7, 18, 21, 24, 32 VCC Positive Power Supply. 10, 14, 15, 17, VEE Device Ground: Ensure the exposed pad is also connected to ground. 27, 28, 29, EP (1) TRUTH TABLE Note 1. L = LOW, H = HIGH, X = don t care. (2) D /D EN OUT /OUT Note 2. H = I I . OUT MOD OFF L HHH L HL H L H XX L H L M9999-082205 2 hbwhelp micrel.com or (408) 955-1690 EN VCC BIASMAX VEE BIASMON MODSET VEE MODMON /FAIL VEE VEE VEE VEE SLOW MD BIAS