UX 2208 155Mbps to 622Mbps Laser Driver Features General Description The UX2208 is a complete CMOS laser driver for 155Mbps to 622Mbps.It consists of a bias current generator with automatic power control (APC), a modulation current driver and a reference voltage generator with temperature compensation. The UX2208 accepts differential PECL inputs and provides complementary output currents. The APC feature allows an optical transmitter to maintain constant average optical +3.0V to +5.5V Supply Voltage Automatic Power Control Temperature-Compensated Modulation Current Programmable slow start Rise and Fall Times less than 600ps Apply to FP、DFB、VCSEL Laser Diode Pin Configuration power by a monitor photodiode, despite changes in laser efficiency with temperature and lifetime. A temperature stabilized reference voltage is provided to simplify laser current programming. Utilizing a resistor at the IMODTC pin can compensate the reduction in slope efficiency of typical laser diodes caused by increased temperature. Figure 1. Pin Configuration QFN 24 Typical Application Circuit Figure 2. Typical Application Circuit 2006 Preliminary Datasheet www.uxfastic.com 1 UX 2208 155Mbps to 622Mbps Laser Driver Pin Description Pin No. Name 1 ENBP 2 VREF1 3 OSADJ 4 IBIASFB Bias-Feedback Current Output. 5 IBIASSET Laser Bias Current-Programming Input. 6 IMODSET Laser Modulation Current-Programming Input. 7 IBIASOUT Laser Bias Current Output. 8,10,12 Function Noninverting Enable Input. Temperature-Compensated Reference Output,connecting to VREF2 internally. Overshoot-Adjust Input. GNDA Ground 9 OUTN Inverting Modulation Output. 11 OUTP Noninverting Modulation Output. 13 VCCA +3.0V to +5.5V Supply Voltage 14 IPIN Monitor Photodiode Current Input. 15 SLWSTRT 16 VREF2 17 IPINSET Slow-Start Capacitor Input. Temperature-Compensated Reference Output. Monitor Photodiode Programming Input. Failout Output. Compatible TTL logic output. Connect FAILOUT 18 FAILOUT to VCC through a 4.7kΩ to 10KΩ pull-up resistor.In normally condition ,it is set low. 19 GNDB Ground 20 VINP Noninverting Data Input 21 VINN Inverting Data Input 22 VCCB +3.0V to +5.5V Supply Voltage 23 IMODTC 24 ENBN 2006 Preliminary Datasheet Connecting a resistor between this pin and ground to set the temperature independency of the modulation current Inverting Enable Input www.uxfastic.com 2 UX 2208 155Mbps to 622Mbps Laser Driver Absolute Maximum Ratings Symbol VCC TA TSTG Parameter Rating Units 6 V Operating ambient -40 to +85 °C Storage temperature -65 to +150 °C Power Supply (VCC-GND) DC Characteristics Symbol Parameter Min. IBIAS Range of Programmable Laser Bias Current VREF Reference Voltage IREF Available Reference Current Vin Total differential inplut signal VMD The dc voltage of input VOH FAILOUT Output High VOL FAILOUT Output Low 2.5 Typ. Max. Units 80 mA 2.8 V 2.65 8 mA 200 1600 0.6 VCC mV V VCC-0.4 V 0.3 V AC Characteristics (RLOAD (at OUTP and OUTN) = 25Ω connected to VCC, Typical values are at VCC = +3.3V and TA = +25°C.) (Note 1) Symbol Parameter Range of IMOD Programmable Modulation Current TR, TF TPWD Modulation-Current Rise and Fall Time Conditions Min. Typ. Minimum differential input swing is 200mVp-p (Note 2) Max. Units 60 mA 600 ps 100 ps IBIAS = 20mA, IMOD = 40mA, 4ns unit interval; measured 400 from 20% to 80% Modulation-Current IBIAS = 20mA, IMOD = 40mA, Pulse-Width Distortion 8ns period Note 1: AC characteristics are guaranteed by design and characterization. Note 2: An 200mVp-p differential is equivalent to complementary 100mVp-p signals on VINP and VINN. 2006 Preliminary Datasheet www.uxfastic.com 3 UX 2208 155Mbps to 622Mbps Laser Driver Typical operating characteristcs (VCC=3.3V, TA=+25℃, unless otherwise noted) Rbiasset VS Ibias 100 Ibias(mA) 80 60 40 20 0 0 10 20 30 Rbiasset(kΩ) 40 50 40 50 Figure 3. Ibias Rmod vs Imod Imod(mA) 70 60 50 40 30 20 10 0 0 10 20 30 Rmod(kΩ) Figure 4. Imod Rpinset vs Ipin 2500 Ipin(uA) 2000 1500 1000 500 0 0 10 20 30 Rpinset(kΩ) 40 50 Figure 5. Ipin 2006 Preliminary Datasheet www.uxfastic.com 4 UX 2208 155Mbps to 622Mbps Laser Driver Package Information Figure 6. QFN24 Package 2006 Preliminary Datasheet www.uxfastic.com 5