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i7032
200 Mbps Laser-Diode Driver Data Sheet
iCreate Technologies Corporation
(c) 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
(c) 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Information contained in this publication is intended through suggestion only and may be superseded by updates.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 Objective Specification Advance Information Description The objective specification contains data for new product development. The information is on products in the design phase. Your designs should not be finalized with this information. 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. Information contained in the data sheet is on products in full production.
Preliminary
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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 support@icreate.com.tw
Revision:3.0 Date: 4/2004 (c) 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
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.
1.2. Features
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: 40J ~ +85J . 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
2.1. Pin configuration
DISABLE IMODTC VINN VINP
20
24
23
22
21
19 18 17
GNDB
VCCB
ENABLE VREF1 ROSADJ IBIASFB IBIASSET IMODSET
1 2 3 4 5
FAILOUT IPINSET VREF2 SLWSTRT IPIN VCCA
i7032-EN 24-pin QFN
16 15 14
6 6
7 8 9 10 11 12
14 13
IBIASOUT
GNDA
Figure 1. i7032-EN pin configuration
(c) 2003 iCreate Technologies Corporation
GNDA
OUTN
GNDA
OUTP
Figure 2. I7032-ET pin configuration
Page 1
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.
i7032
2.2. Pin definition
24-pin QFN Pin No. 1 2 3 4 5 6 7 8,10,12 9 11 13 14 15 16 17 18 19 20 21 22 23 24 32-pin TQFP Pin No. 11 12 13 14 15 16 18 19,21,23 20 22 24,25 26 27 29 30 31
Pin Name ENBABLE VREF1 OSADJ IBIASFB IBIASSET IMODSET IBIASOUT GNDA OUTOUT+ VCCA IPIN SLWSTRT VREF2 IPINSET FAILOUT GNDB VIN+ VINVCCB IMODTC DISABLE NC
Function Non -inverting enable TTL input Temperature-compensated reference output Overshoot-adjust input Bias feedback current output Laser bias current programming input Laser modulation current programming input Laser bias current output Ground Modulation output Modulation output +3.3V to +5V supply voltage Monitor photodiode current input Slow start input Temperature-compensated reference output Monitor photodiode programming input Fail output
2,4,6,9,28 Ground 3 5 7 8 10 1,17,32 Non-inverting PECL data input Inverting PECL data Input +3.3V to +5V supply voltage Connecting a resistor between this pin and ground set the temperature independency of the modulation current Inverting enable TTL input No Connect
(c) 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 VIN+ DRIVER OUT+
VINVCCA VCCB GNDA GNDB
OUT-
IBIASOUT COMPARATOR 4/7 X VCC- 0.4V FIALOUT
ENB+
ENB BIAS GENERATOR
TRANSCONDUCTANCE AMPLIFIER
IPIN SLWSTRT 4/7 XVCC
VREF1,VREF2
IOSADJ
IMODTC
IMODSET
IBIASSET
Figure 3. i7032 block diagram
4. Electrical specifications
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
o o
4.1. DC characteristics
PARAMETER Range of Programmable Laser Bias Current Reference Voltage Available Reference Current Differential Input Voltage TTL High Input TTL Low Input FAILOUT Output High FAILOUT Output Low SYMBOL IBIAS VREF IREF VIL VIH VIL VOH VOL Loaded with 2.7k pull-up resister to Vcc Loaded with 2.7k pull-up resister to Vcc Vcc - 0.3 0.3 100 2 0.8 TA=25 C
o
CONDITIONS
MIN
RPINSET
IBIASFB
TYP
MAX 80
UNITS mA V
2.5 10 1600
mA mVp-p V V V V
(c) 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 3 ICR-DS-i7032001
i7032
4.2. AC characteristics
PARAMETER
Range of Programmable Modulation Current Modulation-Current Rise and Fall Time Modulation-Current Pulsewidth Distortion
SYMBOL
IMOD
CONDITIONS
Minimum differential input swing is 1100mVp-p IBIAS=25mA, IMOD=60mA,measures from 10% to 90%
MIN
TYP
MAX
80
UNITS
mA
tR, tF
1
ns
PWD
100
ps
4.3. Typical operating characteristics
(Vcc=3.3V, TA=+25C, unless otherwise noted)
Figure 4. RBIASSSET vs. IBIAS current
Figure 5. RMODSET vs. Modulation current
Figure 6. RPINSET vs. Monitor current
Figure 7. RMODTC vs. Temperaturecompensated modulation current
(c) 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
The i7032 consists of a laser bias generator with automatic power control (APC), a modulation current driver, and a reference generator with temperature compensation. 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.
5.1. Modulation circuitry
The modulator output stage is designed to drive up to 80mA into 25 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. The input swing is required to completely switch the output stage depends on both ROASDJ and modulation current.
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 2.7K resistor.
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).
ENB0 0 1 1
ENB+ 0 1 0 1 Table 1. i7032 truth table
VREF Off On Off Off
(c) 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. 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.
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.
6.2 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. 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
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 1K) is recommended to an initial point.
(c) 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
RMODSET (K) RMODTC (K)
IMOD=30mA
RMODSET (K) RMODTC (K)
IMOD=15mA
RMODSET (K) RMODTC (K)
2500 2000 1500 1000 500
14.45 8.56 6.08 4.39 3.64
1.68 2.14 2.9 5.05 10.55
17.12 12.03 9.22 7.36 6.19
3.31 4.18 5.64 8.79 14.57
33.13 22.75 17.96 14.77 12.54
7.01 8.78 11.7 14.57 30.15
Table 2. RMODTC and RMODSET selection table
Figure 8. RMODTC vs. RMODSET for various conditions
(c) 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 R3 Rpin C1 0.1uF C5 1uF C6 0.1uF PD VCC C2 0.1uF A C C V GNDA OUTP GNDA OUTN GNDA IBIASOUT P B N E VCC 1 2 1 F E R V J D A S O R 3 4 B F S A I B I 5 T E S S A I B I T E S D O M I 6 12 11 10 9 8 R7 47R 7 C4 1uF i7032_EN C3 NC R6 18R VCC VCC R4 24R LD R1 4.7K
VPIN
U1
8 1 T U O L I A F
7 1 T E S N I P I
6 1 2 F E R V
5 1 T R T S W L S
4 1 N I P I
3 1
R5 NC
DIN+ DINVCC
19 20 21 22
GNDB VINP VINN VCCB IMODTC ENBN
C7 0.1uF
23 24
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
R1 4.7K
R2 0R
R3 Rpin
C1 0.1uF
VPIN
C5 1uF
PD
VCC
C6 0.1uF
LD
U1
8 1 T U O L I A F
7 1 T E S N I P I
6 1 2 F E R V
5 1 T R T S W L S
4 1 N I P I
3 1 A C C V
C2 0.1uF
VCC VCC
R4 24R
R5 NC
DIN+
19
20
21
GNDB
VINP
VINN
VCCB
IMODTC
ENBN
GNDA
OUTP
GNDA
OUTN
GNDA
IBIASOUT
12
11
10
9
8
DINVCC
C3 NC
R6 18R
22
C7 0.1uF
23
24
R7 47R
7
R9 Rs
R8 Rmodtc
P B N E
1 F E R V 2
J D A S O R 3
B F S A I B I 4
T E S S A I B I 5
T E S D O M I 6
C4 1uF
i7032_EN
R10 Rntc
VCC 1
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 : 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
(c) 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 0.80 0.00 0.225 0.19 3.9 2.650 3.90 2.650 0.35 0.00 NOM 0.90 0.02 0.25 0.20 4.00 2.800 4.00 2.800 0.50 0.40 MAX 1.00 0.05 0.275 0.25 4.10 2.950 4.10 2.950 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
(c) 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 1 ccc MIN 0.05 0.95 0.17 0.09 4.90 6.80 4.90 6.80 0.45 0 NOM 1.00 0.22 5.00 7.00 5.00 0.50 0.60 1.00 3.5 MAX 1.20 0.15 1.05 0.27 0.20 5.10 7.20 5.10 7.20 0.75 7 0.08
DIMENSION IN INCH MIN 0.002 0.037 0.007 0.003 0.193 0.267 0.193 0.267 0.018 0 NOM 0.039 0.009 0.197 0.275 0.197 0.275 0.02 0.024 0.039 3.5 MAX 0.047 0.006 0.041 0.011 0.008 0.201 0.283 0.201 0.283 0.029 7 0.003
(c) 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

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