I7032 ETC2 | Alldatasheet
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200 Mbps Laser-Diode Driver
iCreate Technologies Corporation © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. ICR-DS-i7032001 iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
© Copyright 2002 iCreate Technologies Corporation Information contained in this publication is intended through suggestion only and may be superseded by updates. No liability is assume d by iCreat e Technolo gies Co rporation with respe ct to the use of such info rmation o r otherwise and no re presentation or warranty is give n. 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 nam e are registered trademarks of iCreate Technol ogies Corporation. All rights re served. 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 th e 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 preli minary information on new products but not yet fully characterized. The sp ecifications in these data she ets are subje ct to change i n any mann er 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 support@icreate.com.tw Revision:3.0 Date: 4/2004 © 2003 iCreate Technologies Corporation This document contains preliminary information on product but not yet fully characterized. ICR-DS-i7032001 iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
2.2. Pin definition Pin Name 24-pin QFN Pin No. 32-pin TQFP Pin No. Function ENBABLE 1 11 Non -inverting enable TTL input 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 Ground OUT- 9 20 Modulation output OUT+ 11 22 Modulation output VCCA 13 24,25 +3.3V to +5V supply voltage 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 2,4,6,9,28 Ground 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 th e temperature independency of the modulation current DISABLE 24 10 Inverting enable TTL input NC 1,17,32 No Connect © 2003 iCreate Technologies Corporation Page 2 This document contains preliminary information on product but not yet fully characterized. ICR-DS-i7032001 iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
Figure 3. i7032 block diagram
- Electrical specifications
iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
generator with temperature compensation. the node voltage is set by 4/7xVcc reference. results in a feedback current at IBIASFB node. through an external 2.7KΩ resistor. operation (please refer to Table 1). Table 1. i7032 truth table iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
5.5. Slow-start For the lase r safety reason, the i70 32 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 e ach have a 2xVBE temp erature coefficient. Th e reference voltage (VREF1, VREF 2) is adjust ed 2xV BE to greatly cancel these changes. This provides very stable out put curren ts with respect to temperature. Utilizing a resistor a t IMODTC pin can compensate the reduction in slope efficiency of typical laser diodes caused by increased temperature. This feature adds the temperature- compensated portion o f the modula tion current. Please ref er 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, t he clo sed loop scheme should be adopted. The voltage at I PIN is equal to 4/7xVcc. The auto matic power control lo op increases or decreases IBIASFB such that the current fro m the monitor photod iode remains constant. Knowing the monitor photodiod e current at t he desired output po wer, we can determine the RPINSET value from 4.3. Typical operating characteristics figure 6. The automatic power control circuit can adjust the b ias current 50mA from the initial set point. This f eature makes the laser driver circuit reasonably insensitive to variations of laser threshold from lot to lot. The bias setting can b e determined using the laser threshold current or the midpoint of the highest and lowest expected threshold value.
6.2 Setting modulation current
When t he temperature-inde pendent modulation current is u sed, the ext ernal resistor connected t o IMODSET pin can be used to set the modulation current and IMODT C pin should be connect ed to VCC while the temperature- compensated modulation is used, resistors a t the IMODSET and IMODTC p ins set th e amplitude of the modu lation curre nt ( please refer to 7. Typical application circu its, figure 9 and figure 10). The resistor R MODTC set s the temperature- stable portion of the modulation current while the resistor R MODTC sets the temperature-increasing portion of the modulation current. By varying the value of R MODTC with respect to RMODSET, the positive temperature coefficient can be set from 2500 ppm/ °C to 500 ppm/ °C. Ta ble 2 is th e reference value of how the modulation curren t changes with resistan ce over t emperature. Figure 8 sh ows a family of curves which depict the relationship b etween temperature coefficients and constant modulation currents.
6.3 Rise/fall time and overshoot
The rise/fall time and overshoot of i7032 can be adjust ed by an external resistor at ROSADJ pin, in creasing this re sistor slows the rise/fall time and reduces overshoot in th e modulation signal. A smaller resist or value (ar ound 1KΩ) is recommended to an initial po int. © 2003 iCreate Technologies Corporation Page 6 This document contains preliminary information on product but not yet fully characterized. ICR-DS-i7032001 iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
Table 2. RMODTC and RMODSET selection table Figure 8. RMODTC vs. RMODSET for various conditions iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
Figure 11. Package outline –24-pin QFN iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
Figure 12. Package outline –32-pinTQFP iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
This document contains preliminary information on product but not yet fully characterized. ICR-DS-i7032001 iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.
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. ICR-DS-i7032001 iCreate Technologies Corporation reserves the right to change the specification in any manner without notice.