SDH/SONET 2.5Gbps LASER DIODE DRIVER Micrel, Inc. FEATURES ■ ■ ■ ■ ■ ■ ■ ■ SY88922 SY88922 DESCRIPTION Up to 2.5Gbps operation 25mA peak drive current Separate modulation control Separate output enable for laser safety Differential inputs for data 75KΩ input pulldown resistor Designed for use with SY88923, SY88904 or SY88905 Available in a tiny 10-pin (3mm) MSOP The SY88922 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 SY88922 utilizes the high performance bipolar ASSET™ technology. APPLICATIONS ■ ■ ■ ■ ■ 1.25Gbps Gigabit Ethernet 531Mbps and 1062Mbps Fibre Channel 622Mbps SONET Gigabit Interface Converter 2.5Gb/s SDH/SONET BLOCK DIAGRAM VCC REXT OUT OUT RSER DIN Internal Logic DIN IMOD EN BIAS Control to Laser Diode 40X VCC GND Modulation Control GND RSET VREF RSET M9999-091906 [email protected] or (408) 955-1690 Rev.: D 1 Amendment: /0 Issue Date: September 2006 Micrel, Inc. SY88922 PACKAGE/ORDERING INFORMATION Ordering Information 9 OUT Part Number Package Type Operating Range Package Marking Lead Finish 8 /OUT SY88922KC K10-1 Commercial 922 Sn-Pb VREF 4 7 GND SY88922KCTR(1) K10-1 Commercial 922 Sn-Pb RSET 5 6 GND SY88922KG K10-1 Commercial 922 with Pb-Free bar-line indicator Pb-Free NiPdAu SY88922KGTR(1) K10-1 Commercial 922 with Pb-Free bar-line indicator Pb-Free NiPdAu /EN 1 10 VCC DIN 2 /DIN 3 MSOP K10-1 10-Pin MSOP (K10-1) Note: 1. Tape and Reel. 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. M9999-091906 [email protected] or (408) 955-1690 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 = 0mA 2 Micrel, Inc. SY88922 ABSOLUTE MAXIMUM RATINGS(1) Symbol Value Unit VCC Power Supply Voltage Rating 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 TJ Maximum Operating Junction Temperature +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 θJA Thermal Resistance of Package to Ambient(2) COUT Capacitance on OUT + /OUT 1500 to 50,000 Ω 113 °C/W 2.5 typical pf Notes: 1. The voltage drop across REXT and RSER plus Laser Diode should not be greater than 2V. 2. Still air without heatsink. DC ELECTRICAL CHARACTERISTICS GND = 0V; VCC = +5.0V ±10%; TA = 0°C to + 85°C TA = 0°C Symbol Parameter TA = +25°C Min. Typ. Max. Min. Typ. TA = +85°C Max. Min. Typ. Max. Unit VIH Input HIGH Voltage (DIN, /DIN, /EN) VCC–1165 — VCC–880 VCC–1165 — VCC–880 VCC–1165 — VCC–880 mV VIL Input LOW Voltage (DIN, /DIN, /EN) VCC–1810 — VCC–1475 VCC–1810 — VCC–1475 VCC–1810 — VCC–1475 mV 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. M9999-091906 [email protected] or (408) 955-1690 3 Micrel, Inc. SY88922 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 tpd D Propagation Delay DIN - OUT — — 1000 — 500 1000 — — 1000 ps tpd EN Propagation Delay /EN - OUT — — 1000 — 450 1000 — — 1000 ps tr tf Rise/Fall Time (20% to 80%) — — 160 — 110 160 — — 160 ps IOR Output Current Ringing(2) — — 10 — — 10 — — 10 % Notes: 1. REXT = RSER = 25Ω ±1%, RSER connects to VCC directly without Laser Diode. 2. IOH = 5 to 25mA 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) M9999-091906 [email protected] or (408) 955-1690 4 8.0K 10K 12K Conditions Load = 25Ω SY88922 Micrel, Inc. APPLICATION EXAMPLE FOR 3-CHIP SET SOLUTION GBIC Terminal TX_DATA+ TX_DATA– VCC DIN DIN LOSOUT EN VREF RSET 20kΩ VREF GND SY88922 VCC IBIAS GND SY88905 VCC LOS VCC OUT RSER VCC 0.1µF 20kΩ 20kΩ OUT MD IBIAS SET IBIAS FB IPIN SET DIN DIN 24Ω LOSLVL BLM21A102S VCC Laser Module The value of RSER depends on the Laser Diode. VCC 82Ω LOSIN EN SY88923 VREF 130Ω Laserdiode REXT 1000pF 82Ω 68Ω 82Ω Photodiode 130Ω 200Ω 130Ω ENABLE/DISABLE VCC DOUT DOUT GND 0.1µF 68Ω 82Ω 5 M9999-091906 [email protected] or (408) 955-1690 RX_LOS RX_DATA+ RX_DATA– VCC 20kΩ 200Ω 130Ω Micrel, Inc. SY88922 10 LEAD MSOP (K10-1) Rev. 00 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’s use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. M9999-091906 [email protected] or (408) 955-1690 6