MAX3738

 

Part Number	Replacement	Explanation

Description

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The MAX3738 is a +3.3V laser driver designed for multirate transceiver modules with data rates from 1Gbps to 4.25Gbps. Lasers can be DC-coupled to the MAX3738 for reduced component count and ease of multirate operation.

Laser extinction ratio control (ERC) combines the features of automatic power control (APC), modulation compensation, and built-in thermal compensation. The APC loop maintains constant average optical power. Modulation compensation increases the modulation current in proportion to the bias current. These control loops, combined with thermal compensation, maintain a constant optical extinction ratio over temperature and lifetime.

The MAX3738 accepts differential data input signals. The wide 5mA to 60mA (up to 85mA AC-coupled) modulation current range and up to 100mA bias current range, make the MAX3738 ideal for driving FP/DFB lasers in fiber optic modules. External resistors set the required laser current levels. The MAX3738 provides transmit disable control (TX_DISABLE), single-point fault tolerance, bias-current monitoring, and photocurrent monitoring. The device also offers a latched failure output (TX_FAULT) to indicate faults, such as when the APC loop is no longer able to maintain the average optical power at the required level. The MAX3738 is compliant with the SFF-8472 transmitter diagnostic and SFP MSA timing requirements.

The MAX3738 is offered in a 4mm x 4mm, 24-pin thin QFN package and operates over the extended -40°C to +85°C temperature range.

MAX3738: Typical Operating Circuit Enlarge+

Key Features

• Single +3.3V Power Supply
• 47mA Power-Supply Current
• 85mA Modulation Current
• 100mA Bias Current
• Automatic Power Control (APC)
• Modulation Compensation
• On-Chip Temperature Compensation
• Self-Biased Inputs for AC-Coupling
• Ground-Referenced Current Monitors
• Laser Shutdown and Alarm Outputs
• Enable Control and Laser Safety Feature

Applications/Uses

• 1Gbps/2Gbps/4Gbps Fibre Channel SFF/SFP and GBIC Transceivers
• Gigabit Ethernet SFF/SFP and GBIC Transceivers
• Multirate OC-24 to OC-48 FEC Transceivers