+3.3V, 622Mbps SDH/SONET Laser Driver with Automatic Power Control

Lowest-Power 622Mbps Laser Driver

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The MAX3668 is a complete, +3.3V laser driver with automatic power control (APC) circuitry for SDH/SONET applications up to 622Mbps. It accepts differential PECL inputs, provides bias and modulation currents, and operates over a temperature range of -40°C to +85°C.

An APC feedback loop is incorporated to maintain a constant average optical power over temperature and lifetime. The wide modulation current range of 5mA to 75mA and bias current of 1mA to 80mA are easy to program, making this product ideal for use in various SDH/SONET applications.

The MAX3668 also provides enable control and a failure-monitor output to indicate when the APC loop is unable to maintain the average optical power. The MAX3668 is available in a 5mm 32-pin TQFP package as well as in dice.
MAX3668: Typical Operating Circuit MAX3668: Typical Operating Circuit Enlarge+

Key Features

  • Single +3.3V or +5.0V Operation
  • 38mA Supply Current at +3.3V
  • Programmable Modulation Current from 5mA to 75mA
  • Programmable Bias Current from 1mA to 80mA
  • Rise/Fall Time < 200ps
  • Automatic Average Power Control with Failure Monitor
  • Complies with ANSI, ITU, and Bellcore SONET/SDH Specifications
  • Enable Control


  • 622Mbps SDH/SONET Access Nodes
  • Laser Driver Transmitters
  • Section Regenerators

Technical Documents

App Note 596 HFAN-02.2.0: Extinction Ratio and Power Penalty
Product Reliability Reports: MAX3668.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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