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MAXIM INTEGRATED PRODUCTS MAX3668† Quick User Guide +3.3V, 622Mbps SDH SONET Laser Driver with Automatic Power Control

Summary

The MAX3668 is a specialized +3.3V laser driver designed for high-speed SDH/SONET networking applications up to 622Mbps. Featuring crucial automatic power control (APC) circuitry, this device ensures stable optical power over wide temperature ranges while allowing programmable bias and modulation currents. This technical guide details the product's full operational specifications, including electrical characteristics, failure monitoring features, and integration guidelines. It is essential documentation for engineers selecting components for reliable access nodes and regenerators in telecommunication systems.

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Page 1 Text Content

19-4799; Rev 4; 2/05

+3.3V, 622Mbps SDH/SONET

Laser Driver with Automatic Power Control General Description Features The MAX3668 is a complete, +3.3V laser driver with Single +3.3V or +5.0V Operation

automatic power control (APC) circuitry for SDH/SONET

38m A Supply Current at +3.3V

applications up to 622Mbps. It accepts differential PECL inputs, provides bias and modulation currents,

Programmable Modulation Current from

and operates over a temperature range of -40°C to

5m A to 75m A

Programmable Bias Current from 1m A to 80m A

An APC feedback loop is incorporated to maintain a constant average optical power over temperature and Rise/Fall Time <200ps lifetime. The wide modulation current range of 5m A to

Automatic Average Power Control with Failure

75m A and bias current of 1m A to 80m A are easy to

BI AS AX

Monitor

program, making this product ideal for use in various EN AB LE SDH/SONET applications. Complies with ANSI, ITU, and Bellcore

OD SE

The MAX3668 also provides enable control and a failure- SONET/SDH Specifications

monitor output to indicate when the APC loop is unable AP CS ET

Enable Control

to maintain the average optical power. The MAX3668 is

Ordering Information

available in a 5mm 32-pin TQFP package as well as in CA PC dice.

PART TEMP RANGE PIN-PACKAGE

FA IL

GN MAX3668EHJ -40°C to +85°C 32 TQFP (5mm x 5mm)

Applications

MAX3668EHJ+ -40°C to +85°C 32 TQFP (5mm x 5mm)

622Mbps SDH/SONET Access Nodes

MAX3668E/D Note Dice*

Laser Driver Transmitters Note: Dice are designed to operate over a -40°C to +140°C

junction temperature (Tj) range, but are tested and guaranteed

Section Regenerators

at TA = +25°C. *Contact factory for availability. +Denotes lead-free package. Pin Configuration appears at end of data sheet.

Typical Operating Circuit

LASER

DATA+ RD

MAX3693 5Ω

DATA- OUT+

4:1 CD

MAX3668 RFILT

SERIALIZER 1.0µF

CFILT

CLOCK GEN

FERRITE BEAD

CMD 1000p F

†Covered by U.S. Patent numbers 5,802,089 and 5,883,910

Maxim Integrated Products

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Page Summary Contents For MAXIM INTEGRATED PRODUCTS MAX3668† Quick User Guide +3.3V, 622Mbps SDH SONET Laser Driver with Automatic Power Control

Page 1 19-4799; Rev 4; 2/05 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control General Description Features The MAX3668 is a complete, +3.3V laser driver with Single +3.3V or +5.0V Operation ...
Page 2 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control ABSOLUTE MAXIMUM RATINGS Supply Voltage, VCC .............................................-0.5V to +7.0V Voltage at BIAS ...............
Page 3 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control AC ELECTRICAL CHARACTERISTICS (VCC = +3.14V to +5.5V, load as shown in Figure 2, TA = -40°C to +85°C, unless otherwise noted. Typical...
Page 4 RA ND OM JI TT ER (p s p -p +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) EYE DIAGRAM (622Mbps...
Page 5 BI AS UR RE NT (m A) +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control Typical Operating Characteristics (continued) (VCC = +3.3V, TA = +25°C, unless otherwise noted.) AVAILABLE BIAS ...
Page 6 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control DATA+ OUT+ OUT- DATA- ENABLE BIASIBIAS MAX3668 FAILURE DETECTOR MODSET BIASMAX APCSETCAPC CAPC RAPCSETRBIASMAXRMODSET Figure 3. Funct...
Page 7 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control Automatic Power Control Short-Circuit Protection To maintain constant average optical power, the The MAX3668 provides short-circuit p...
Page 8 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control Programming the APC Loop If t1 equals 80 consecutive unit intervals without a tran- When the MAX3668’s APC feature is used, program t...
Page 9 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control ratio is re = 6.6 (8.2d B), the operating temperature is Wire Bonding Die -40°C to +85°C, and the laser diode has the following For h...
Page 10 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control EN AB LE BI AS AX Pin Configuration GN Chip Topography OD SE FA IL GN N. C. AP CS ET TOP VIEW GN N. C. GND VCC ENABLE BIASMAX 1VCC VC...
Page 11 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control Package Information PACKAGE OUTLINE, 32L TQFP, 5x5x1.0mm, EP OPTION (Package information continues on next page.) L, TQ FP .E
Page 12 +3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control Package Information (continued) PACKAGE OUTLINE, 32L TQFP, 5x5x1.0mm, EP OPTION Maxim makes no warranty, representation or guarantee ...

Manual Details

Brand Maxim Integrated
Pages 12
File Size 744.72 KB
Published May 26, 2026
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Frequently Asked Questions

What does the Automatic Power Control (APC) circuit maintain?

The APC feedback loop maintains a constant average optical power over temperature.

What signal inputs and outputs does the MAX3668 handle?

It accepts differential PECL inputs and provides configurable bias and modulation currents.

What is the operational frequency range of this laser driver?

The device supports applications up to 622Mbps for SDH/SONET.

What are the required temperature specifications for operation?

The MAX3668 operates over a temperature range of -40°C to +85°C.