Create i7032 200 Mbps Laser-Diode Driver Data Sheet iCreate Technologies Corporation © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. ICR-DS-i7032001 i7032 © Copyright 2002 iCreate Technologies Corporation Information contained in this publication is intended through suggestion only and may be superseded by updates. No liability is assumed by iCreate Technologies Corporation with respect to the use of such information or otherwise and no representation or warranty is given. Use of iCreate’s products as critical components in life support systems is not authorized. No part of this document may be reproduced or transmitted in any form or by any means for any purpose without the permission of iCreate. No licenses are conveyed, implicitly or otherwise, under any intellectual property rights. The iCreate logo and name are registered trademarks of iCreate Technologies Corporation. All rights reserved. All other trademarks mentioned herein are the property of their respective companies. Data sheet marking iCreate uses various markings in the data sheet to designate each document phase as it relates to the product development stage. Marking Description Objective Specification The objective specification contains data for new product development. Advance Information The information is on products in the design phase. Your designs should not be finalized with this information. Preliminary This is preliminary information on new products but not yet fully characterized. The specifications in these data sheets are subject to change in any manner without notice. No Marking Information contained in the data sheet is on products in full production. For more information please contact: iCreate Technologies Corporation No. 6, Technology Rd. V, Science-Based Industrial Park, Hsinchu, Taiwan 300 Phone +886-3-579-0000 Fax +886-3-579-0077 e-mail [email protected] Revision:3.0 Date: 4/2004 © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. ICR-DS-i7032001 i7032 +3.3V to +5.0V, 200Mbps Laser-Diode Driver 1. Introduction 1.1. General description 1.2. Features The i7032 is the 3.3V to 5V, 200Mbps laser-diode driver with automatic power control (APC). Both accept differential PECL inputs and provide complementary output currents. A temperature-compensated reference voltage is provided for laser bias and modulation current programming. This allows maximum 80mA to be programmed for bias and modulation current with two external resistors. The i7032 provides adjustable temperaturecompensated modulation current to keep the optical extinction rate within specifications over the operation temperature range. The APC circuits incorporated with a monitor photo-diode and two external resistors maintain laser’s average power. A failure-monitor output is provided to indicate when the APC loop is unable to maintain average power. To prevent laser diode damage, an integrated soft-start circuit is provided. The output load can be DC and AC coupled in both 3.3V and 5V applications. The i7032 is in 24-pin QFN package. Rise / fall time less than 1 ns. Maximum 80mA bias current. Maximum 80mA modulation current. Differential PECL inputs. Automatic Power Control (APC). +3.3V to +5V supply voltage. On chip temperature-compensated reference voltage. Wide operation temperature range: 40℃ ~ +85℃. Integrated soft-start circuit. On chip temperature-compensated modulation current. 1.3. Applications 155Mbps SDH/SONET Laser-Diode Transmitters 1.4 Ordering information Part i7032-EN i7032-ET Pin-Package 24 QFN (4mmX4mm) 32 TQFP (5mmX5mm) 2. Pin configuration and definition VINP GNDB IMODTC 23 VINN 24 VCCB DISABLE 2.1. Pin configuration 22 21 20 19 ENABLE 1 18 FAILOUT VREF1 2 17 IPINSET ROSADJ 3 IBIASFB 4 i7032-EN 24-pin QFN 16 VREF2 15 SLWSTRT 8 9 10 GNDA 7 11 12 OUTP VCCA GNDA IPIN 14 13 OUTN 14 GNDA 5 66 IBIASOUT IBIASSET IMODSET Figure 1. i7032-EN pin configuration Figure 2. i7032-ET pin configuration © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 1 ICR-DS-i7032001 i7032 2.2. Pin definition ENBABLE 1 32-pin TQFP Pin No. 11 VREF1 2 12 Temperature-compensated reference output OSADJ 3 13 Overshoot-adjust input IBIASFB 4 14 Bias feedback current output IBIASSET 5 15 Laser bias current programming input IMODSET 6 16 Laser modulation current programming input IBIASOUT 7 18 Laser bias current output GNDA 8,10,12 19,21,23 OUT- 9 20 Modulation output OUT+ 11 22 Modulation output VCCA 13 24,25 IPIN 14 26 Monitor photodiode current input SLWSTRT 15 27 Slow start input VREF2 16 29 Temperature-compensated reference output IPINSET 17 30 Monitor photodiode programming input FAILOUT 18 31 Fail output GNDB 19 VIN+ 20 3 Non-inverting PECL data input VIN- 21 5 Inverting PECL data Input VCCB 22 7 +3.3V to +5V supply voltage IMODTC 23 8 Connecting a resistor between this pin and ground set the temperature independency of the modulation current DISABLE 24 10 Inverting enable TTL input Pin Name NC 24-pin QFN Pin No. Function Non -inverting enable TTL input Ground +3.3V to +5V supply voltage 2,4,6,9,28 Ground 1,17,32 No Connect © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 2 ICR-DS-i7032001 i7032 3. Block diagram PREAMPLIFIER DRIVER VIN+ OUT+ VIN- OUT- VCCA VCCB GNDA GNDB IBIASOUT COMPARATOR 4/7 X VCC- 0.4V FIALOUT ENB+ ENB - TRANSCONDUCTANCE AMPLIFIER BIAS GENERATOR IPIN SLWSTRT RPINSET IBIASFB IBIASSET IMODSET IMODTC IOSADJ VREF1,VREF2 4/7 X VCC Figure 3. i7032 block diagram 4. Electrical specifications o o Vcc=VccA=VccB=+3.0V to +5.5V, TA= -40 C to 85 C, unless otherwise noted. Typical values are at o Vcc=VccA=VccB=+3.3V, TA=+25 C 4.1. DC characteristics PARAMETER SYMBOL Range of Programmable Laser Bias Current IBIAS Reference Voltage VREF Available Reference Current IREF CONDITIONS MIN o TYP MAX UNITS 80 mA 2.5 TA=25 C Differential Input Voltage VIL 100 TTL High Input VIH 2 TTL Low Input VIL V 10 mA 1600 mVp-p V 0.8 FAILOUT Output High VOH Loaded with 2.7kΩ pull-up resister to Vcc FAILOUT Output Low VOL Loaded with 2.7kΩ pull-up resister to Vcc Vcc - 0.3 © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. V V 0.3 V Page 3 ICR-DS-i7032001 i7032 4.2. AC characteristics PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Range of Programmable Modulation Current IMOD Minimum differential input swing is 1100mVp-p 80 mA Modulation-Current Rise and Fall Time tR, tF IBIAS=25mA, IMOD=60mA,measures from 10% to 90% 1 ns Modulation-Current Pulsewidth Distortion PWD 100 ps 4.3. Typical operating characteristics (Vcc=3.3V, TA=+25°C, unless otherwise noted) Figure 4. RBIASSSET vs. IBIAS current Figure 6. RPINSET vs. Monitor current Figure 5. RMODSET vs. Modulation current Figure 7. RMODTC vs. Temperaturecompensated modulation current © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 4 ICR-DS-i7032001 i7032 5. Product description A monitor photodiode mounted in the laser package is used to convert the optical power into a monitor current. This current flow into the IPIN input. The IPINSET current mirror draws current away from IPIN node. When the current into IPIN node equals the current drawn away by IPINSET, the node voltage is set by 4/7xVcc reference. When the monitor current exceeds IPINSET, the IPIN node voltage will be forced higher. If the monitor current decreases, the IPIN node voltage is decreased. In either case the voltage change results in a feedback current at IBIASFB node. The i7032 consists of a laser bias generator with automatic power control (APC), a modulation current driver, and a reference generator with temperature compensation. 5.1. Modulation circuitry The modulator output stage is designed to drive up to 80mA into 25Ω load in either ACcouple or DC-coupled mode. The amplitude of the modulation current is set with a resistor at IMODSET pin or with resistors at IMODSET and IMODTC pins. Please refer to 4.3. Typical operating characteristics figure 5 and figure 7 for more information. 5.3. APC failure Indicator The i7032 provides an APC failure indicator to indicate an APC loop tacking failure. FAILOUT is set low when the APC loop can no longer adjust the bias current to maintain the desired monitor current. This output is pulled up to Vcc through an external 2.7KΩ resistor. The input swing is required to completely switch the output stage depends on both ROASDJ and modulation current. 5.2. Automatic power control The amplitude of DC current to the laser diode is determined by setting the resistor at IBIASSET pin (Please refer to 4.3. Typical operating characteristics figure 4). To maintain constant average optical power, i7032 incorporates a control loop to compensate for change in laser threshold current over temperature and lifetime. 5.4. Enable inputs The i7032 provides complementary enable inputs (ENB+, ENB-). The laser is disabled by reducing the reference voltage outputs (VREF1, VREF2). Both ENB+ and ENB- pins can not be floating and only one logic state enables laser operation (please refer to Table 1). ENB- ENB+ VREF 0 0 Off 0 1 On 1 0 Off 1 1 Off Table 1. i7032 truth table © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 5 ICR-DS-i7032001 i7032 5.5. Slow-start For the laser safety reason, the i7032 sets start-up time for enabling a laser diode by an external capacitor connected to ground. 5.6. Temperature compensation The i7032 output current is programmed by current mirrors. These mirrors each have a 2xVBE temperature coefficient. The reference voltage (VREF1, VREF2) is adjusted 2xVBE to greatly cancel these changes. This provides very stable output currents with respect to temperature. Utilizing a resistor at IMODTC pin can compensate the reduction in slope efficiency of typical laser diodes caused by increased temperature. This feature adds the temperaturecompensated portion of the modulation current. Please refer to 4.3. Typical operating characteristics figure 7 for more details. 6. Application information 6.1 Typical closed loop application When the laser-diode/VCSEL includes a monitor photodiode, the closed loop scheme should be adopted. The voltage at IPIN is equal to 4/7xVcc. The automatic power control loop increases or decreases IBIASFB such that the current from the monitor photodiode remains constant. Knowing the monitor photodiode current at the desired output power, we can determine the RPINSET value from 4.3. Typical operating characteristics figure 6. The automatic power control circuit can adjust the bias current 50mA from the initial set point. This feature makes the laser driver circuit reasonably insensitive to variations of laser threshold from lot to lot. The bias setting can be determined using the laser threshold current or the midpoint of the highest and lowest expected threshold value. 6.2 Setting modulation current When the temperature-independent modulation current is used, the external resistor connected to IMODSET pin can be used to set the modulation current and IMODTC pin should be connected to VCC while the temperaturecompensated modulation is used, resistors at the IMODSET and IMODTC pins set the amplitude of the modulation current ( please refer to 7. Typical application circuits, figure 9 and figure 10). The resistor RMODTC sets the temperaturestable portion of the modulation current while the resistor RMODTC sets the temperature-increasing portion of the modulation current. By varying the value of RMODTC with respect to RMODSET, the positive temperature coefficient can be set from 2500 ppm/°C to 500 ppm/°C. Table 2 is the reference value of how the modulation current changes with resistance over temperature. Figure 8 shows a family of curves which depict the relationship between temperature coefficients and constant modulation currents. 6.3 Rise/fall time and overshoot adjustment The rise/fall time and overshoot of i7032 can be adjusted by an external resistor at ROSADJ pin, increasing this resistor slows the rise/fall time and reduces overshoot in the modulation signal. A smaller resistor value (around 1KΩ) is recommended to an initial point. © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 6 ICR-DS-i7032001 i7032 TEMPCO (ppm/°C) IMOD=50mA IMOD=30mA IMOD=15mA RMODSET RMODTC RMODSET RMODTC RMODSET RMODTC (KΩ) (KΩ) (KΩ) (KΩ) (KΩ) (KΩ) 2500 14.45 1.68 17.12 3.31 33.13 7.01 2000 8.56 2.14 12.03 4.18 22.75 8.78 1500 6.08 2.9 9.22 5.64 17.96 11.7 1000 4.39 5.05 7.36 8.79 14.77 14.57 500 3.64 10.55 6.19 14.57 12.54 30.15 Table 2. RMODTC and RMODSET selection table Figure 8. RMODTC vs. RMODSET for various conditions © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 7 ICR-DS-i7032001 i7032 7. Typical application circuits 7.1. Application circuit with temperature-independent modulation current VCC VCC R2 0R R1 4.7K R3 Rpin C5 1uF C1 0.1uF C6 0.1uF PD VPIN LD VCC 8 1 U1 19 DIN+ 20 DIN- 21 VCC 22 C7 0.1uF 23 24 GNDB 6 1 7 1 T U O LI A F 5 1 2 F E R V T E S N I PI C2 0.1uF 3 1 4 1 T R T S W L S OUTP VINN GNDA VCCB OUTN IMODTC 11 R6 18R 9 8 R7 47R 7 IBIASOUT VCC 1 J D A S O R 1 F E R V 3 2 T E S S AI BI B F S AI BI 5 4 T E S D O M I C3 NC 10 GNDA ENBN R5 NC 12 GNDA VINP P B N E VCC VCC R4 24R A C C V N I PI C4 1uF i7032_EN 6 R11 Rosadj R12 Rbias R13 Rmodset Rmodset : Reserve if need. Rbias : Reserve if need. Rpin : Setting for LD current. Rmodtc : Setting for modulation current & Temperature compensation control. R5 & C3 : are optional for overshooting improvement. Rs & Rntc : Modulation temperature compensation if need. Check VPIN : 4/7*VCC to make sure APC functional work. Figure 9. Typical application circuit with temperature-independent modulation current 7.2. Application circuit with temperature-compensated modulation current VCC VCC C6 0.1uF C5 1uF C1 0.1uF R3 Rpin R2 0R R1 4.7K PD LD VPIN VCC U1 19 DIN+ 20 DIN- 21 VCC 22 23 C7 0.1uF 24 8 1 GNDB R8 Rmodtc T R T S W L S R4 24R A C C V N I P I GNDA VINP OUTP GNDA VCCB OUTN IMODTC GNDA ENBN IBIASOUT 1 F E R V P B N E VCC 1 2 J D A S O R 3 T E S S A I B I B F S AI BI 4 5 R11 Rosadj VCC VCC C2 0.1uF 3 1 4 1 VINN R9 Rs R10 Rntc 2 F E R V T E S N I P I T U O LI A F 5 1 6 1 7 1 T E S D O M I R5 NC 12 11 10 C3 NC R6 18R 9 8 R7 47R 7 C4 1uF i7032_EN 6 R12 Rbias R13 Rmodset Rmodset : Reserve if need. Rbias : Reserve if need. Rpin : Setting for LD current. Rmodtc : Setting for modulation current & Temperature compensation control. R5 & C3 : Overshoot filter. Rs & Rntc : Modulation temperature compensation if need. Check VPIN : 4/7*VCC to make sure APC functional work. Figure 10. Typical application circuit with temperature-compensated modulation current © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 8 ICR-DS-i7032001 i7032 8. Package outline Figure 11. Package outline –24-pin QFN DIMENSION IN MM SYMBOL A A1 b C D D2 E E2 e L y MIN NOM MAX 0.80 0.00 0.225 0.19 3.9 2.650 3.90 2.650 0.90 0.02 0.25 0.20 4.00 2.800 4.00 2.800 0.50 0.40 1.00 0.05 0.275 0.25 4.10 2.950 4.10 2.950 0.35 0.00 0.45 0.076 DIMENSION IN INCH MIN NOM MAX 0.035 0.035 0.039 0.000 0.0008 0.002 0.009 0.010 0.011 0.0075 0.008 0.0098 0.1535 0.1575 0.1615 0.104 0.110 0.116 0.1535 0.1575 0.1615 0.104 0.110 0.116 0.0197 0.014 0.016 0.018 0.000 0.003 © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 9 ICR-DS-i7032001 i7032 Figure 12. Package outline –32-pinTQFP DIMENSION IN MM SYMBOL A A1 A2 b C D1 D E1 E e L L1 θ1 ccc DIMENSION IN INCH MIN NOM MAX MIN NOM MAX 0.05 0.95 0.17 0.09 4.90 6.80 4.90 6.80 0.45 0° 1.20 0.15 1.05 0.27 0.20 5.10 7.20 5.10 7.20 0.75 7° 0.08 0.002 0.037 0.007 0.003 0.193 0.267 0.193 0.267 0.018 0° 0.039 0.009 0.197 0.275 0.197 0.275 0.02 0.024 0.039 3.5° 0.047 0.006 0.041 0.011 0.008 0.201 0.283 0.201 0.283 0.029 7° 0.003 1.00 0.22 5.00 7.00 5.00 0.50 0.60 1.00 3.5° © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. Page 10 ICR-DS-i7032001 This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. ICR-DS-i7032001 iCreate Technologies Corporation No. 6, Technology Rd. V, Science-Based Industrial Park, Hsinchu, Taiwan 300 Tel: +886-3-579-0000 Fax: +886-3-579-0077 This document contains preliminary information on product but not yet fully characterized. iCreate Technologies Corporation reserves the right to change the specification in any manner without notice. ICR-DS-i7032001