3.2Gbps SFP VCSEL Driver with Diagnostic Monitors

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The MAX3740A is a high-speed VCSEL driver for small-form-factor (SFF) and small-form-factor pluggable (SFP) fiber optic LAN transmitters. It contains a bias generator, a laser modulator, and comprehensive safety features. The automatic power control (APC) adjusts the laser bias current to maintain average optical power over changes in temperature and laser properties. The driver accommodates common cathode and differential configurations.

The MAX3740A operates up to 3.2Gbps. It can switch up to 15mA of laser modulation current and source up to 15mA of bias current. Adjustable temperature compensation is provided to keep the optical extinction ratio within specifications over the operating temperature range. The MAX3740A interfaces with the Dallas DS1858 to meet SFF-8472 timing and diagnostic requirements. The MAX3740A accommodates various VCSEL packages, including low-cost TO-46 headers.

The MAX3740A safety circuit detects faults that could cause hazardous light levels and disables the VCSEL output. The safety circuits are compliant with SFF and SFP multisource agreements (MSA).

The MAX3740A is available in a compact 4mm x 4mm, 24-pin thin QFN package and operates over the -40°C to +85°C temperature range.
MAX3740A: Typical Operating Circuit MAX3740A: Typical Operating Circuit Enlarge+

Key Features

  • Supports all SFF-8472 Digital Diagnostics
  • 2mA to 15mA Modulation Current
  • 1mA to 15mA Bias Current
  • Optional Peaking Current to Improve VCSEL Edge Speed
  • Supports Common Cathode and Differential Configuration
  • Automatic Power Control
  • Safety Circuits Compliant with SFF and SFP MSAs
  • 4mm x 4mm 24-Pin Thin QFN Package


  • Fibre Channel Optical Transmitters
  • Gigabit Ethernet Optical Transmitters
  • InfiniBand® Optical Transmitters
  • Multirate (1Gbps to 3.2Gbps) SFF/SFP Modules

See parametric specs for Laser Drivers (20)

Part NumberTarget Oper. Range
Data Rate
Data Rate
minmaxtypmaxmaxSee Notes
MAX3740A 1 to 4.5100032003.355CML1515
$6.93 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX3740AEVKIT: Evaluation Kit for the MAX3740A
Product Reliability Reports: MAX3740A.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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