LASER DIODE DRIVER WTIH OUTPUT ENABLE DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ SY88902 Up to 1.25Gbps operation 25mA peak drive current Separate modulation control Separate output enable for laser safety Differential inputs for data 75KΩ input pulldown resistor Single power supply Designed for use with SY88903 and SY88904 Available in a tiny 10-pin (3mm) MSOP The SY88902 is a high speed current switch for driving a semiconductor laser diode in optical transmission applications. The output current, or modulation current IMOD, is DC current controlled by IRSET, current through the resistor RSET. The output OUT is HIGH when output enable is HIGH. The device incorporates complementary open collector outputs with a capability of driving peak current of 25mA. The resistor REXT must be placed between /OUT and V CC to dissipate the worst case power. R SER is recommended to compensate for laser diode matching issues. The SY88902 utilizes the high performance bipolar ASSET™ technology. APPLICATIONS PIN CONFIGURATIONS /EN 1 ■ ■ ■ ■ 10 VCC DIN 2 9 OUT MSOP K10-1 /DIN 3 8 /OUT VREF 4 7 GND RSET 5 6 GND 1.25Gbps Gigabit Ethernet 531Mbps and 1062Mbps Fibre Channel 622Mbps SONET Gigabit Interface Converter BLOCK DIAGRAM VCC REXT OUT OUT RSER DIN Internal Logic DIN IMOD EN BIAS Control 40X to Laser Diode VCC GND Modulation Control VEE RSET VREF RSET Rev.: C 1 Amendment: /1 Issue Date: July 2000 SY88902 Micrel TRUTH TABLE(1) PIN NAMES Pin Function VCC Most positive power supply input, +5V for PECL operation. GND Ground DIN, /DIN These differential PECL 100K compatible inputs receive NRZ data. /EN This PECL 100K compatible input enables Laser Driver. Modulation current goes to zero when asserted HIGH. OUT, /OUT Open collector outputs from the modulation buffer drive these differential current outputs. VREF Voltage reference for use with RSET. RSET An external resistor sets up the source current for modulation Imod. D D /EN OUT (2) /OUT L H L H L H L L L H X X H H L NOTES: 1. L = LOW, H = HIGH, X = don't care 2. H = IOUT = OmA ABSOLUTE MAXIMUM RATINGS(1) Symbol Rating Value Unit VCC Power Supply Voltage 0 to +7.0 V VI Input Voltage 0 to VCC V IO Output Current 25 mA TA Operating Temperature Range 0 to +85 °C Tstore Storage Temperature Range –55 to +125 °C Ptot Power Dissipation 250 mW NOTE: 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. OPERATIONING CONDITIONS(1) Symbol Rating Value Unit +4.5 to +5.5 V VCC Power Supply Voltage REXT Resistor to Dissipate Power 10 to 50 Ω RSER Laser Diode Serial Resistor 0 to 50 Ω RSET Resistor to Adjust Current 1500 to 50,000 Ω 206 °C/W 2.5 typical pf ΘJA Thermal Resistance of Package to COUT Capacitance on OUT + /OUT Ambient(2) NOTES: 1. The voltage drop across REXT and RSER plus Laser Diode should not be greater than 2V. 2. Still air without heatsink. 2 SY88902 Micrel DC ELECTRICAL CHARACTERISTICS GND = 0V; VCC = +5.0V ±10%; TA = 0˚C to + 85˚C TA = 0°C Symbol Parameter TA = +25°C TA = +85°C Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Unit VCC-880 VCC-1165 — VCC-880 VCC-1165 — VCC-880 mV VCC-1475 VCC-1810 — VCC-1475 VCC-1810 — VCC-1475 mV VIH Input HIGH Voltage (DIN, /DIN, /EN) VCC-1165 — VIL Input LOW Voltage (DIN, /DIN, /EN) VCC-1810 — VREF Reference Voltage — 3.12 — — 3.00 — — 2.80 — V Current(1) IIL Input LOW (DIN, /DIN, /EN) 0.5 — — 0.5 — — 0.5 — — uA IIH Input HIGH Current (DIN, /DIN, /EN) — — 100 — — 100 — — 100 uA ICC Supply Current(2) — 16 25 — 16 25 — 16 25 mA IOL Output LOW Current (/EN = HIGH) — — 500 — — 500 — — 500 uA IOUT Modulation Current 5 15 25 5 15 25 5 15 25 mA IRSET Modulation Control 0.125 — 0.625 0.125 — 0.625 0.125 — 0.625 mA ARSET =IOUT/IRSET 30 38 44 30 38 44 30 38 44 — NOTES: 1. VI = VIL(Min.) 2. IMOD = 25mA. AC ELECTRICAL CHARACTERISTICS(1) IMOD =10mA; GND = 0V; VCC = +5V ±10%; TA = 0˚C to + 85˚C TA = 0°C Symbol Parameter TA = +25°C TA = +85°C Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Unit Conditions tpd D Propagation Delay DIN - OUT — — 1000 — 500 1000 — — 1000 ps IMOD = 10mA tpd EN Propagation Delay /EN - OUT — — 1000 — 450 1000 — — 1000 ps IMOD = 10mA tr tf Rise/Fall Time (20% to 80%) — 200 — — 200 — — 200 — ps IOR Output Current Ringing(2) — — 10 — — 10 — — 10 % NOTES: 1. REXT = RSER = 50Ω ±1%, RSER connects to VCC directly without Laser Diode. 2. IOH = 5 to 25mA 3 SY88902 Micrel APPLICATION EXAMPLE FOR 3-CHIP SET SOLUTION GBIC Terminal +TX_DAT –TX_DATA TX_FAULT TX_DISABLE RX_LOS +RX_DAT –RX_DAT TX_FAULT TX_DISABLE LOSOUT EN DOUT DOUT DIN DIN OC PECL VCC GND VCC REXT OUT VREF DIN DIN VCC OUT RSER IBIAS VCC MD IPIN SET VREF SY88904 RSET VREF SY88902 EN TX_Out PECL LOS LOS LOSLVL SY88903 VCC GND Laser Module VCC GND RWIN VCC 2meg 0.1µf IBIAS SET IBIAS FB VCCDET ILIMIT SET IBIAS SET VREF VCC ILIMIT SET VREF 4 SY88902 Micrel APPLICATION EXAMPLE FOR 3-CHIP SET SOLUTION Gigabit EthernetTerminal +TX_DAT –TX_DATA RX_LOS +RX_DAT –RX_DAT LOSOUT EN DOUT DOUT DIN DIN PECL VCC VEE VCC REXT OUT VREF DIN DIN VBB VLVL OUT RSER IBIAS VCC VCC MD IPIN SET VPIN SET VREF SY88905 RSET VREF SY88902 EN LOSIN LOS SY88903 VCC VEE Laser Module VCC GND IBIAS SET VBIAS SET IBIAS FB IBIAS SET VREF 5 SY88902 Micrel PERFORMANCE CURVES IO and RSET 30 25 IO (mA) 20 15 10 5 0.0 0.0 2.0K 4.0K 6.0K RSET (ohm) PRODUCT ORDERING CODE Ordering Code Package Type Operating Range SY88902KC K10-1 Commercial SY88902KCTR K10-1 Commercial 6 8.0K 10K 12K SY88902 Micrel 10 LEAD MSOP (K10-1) Rev. 00 7 SY88902 Micrel MICREL-SYNERGY TEL 3250 SCOTT BOULEVARD SANTA CLARA CA 95054 USA + 1 (408) 980-9191 FAX + 1 (408) 914-7878 WEB http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated 8