2.7Gbps, Low-Power SFP Laser Drivers

The MAX3735A is a +3.3V laser driver for SFP/SFF applications from 155Mbps up to 2.7Gbps. The device accepts differential input data and provides bias and modulation currents for driving a laser. DC-coupling to the laser allows for multirate applications and reduces the number of external components. The MAX3735A is fully compliant with the SFP MSA timing and the SFF-8472 transmit diagnostic requirements.

An automatic power-control (APC) feedback loop is incorporated to maintain a constant average optical power over temperature and lifetime. The wide modulation current range of 10mA to 60mA (up to 85mA AC-coupled) and bias current of 1mA to 100mA make this product ideal for driving FP/DFB laser diodes in fiber-optic modules. The resistor range for the laser current settings is optimized to interface with the DS1858 SFP controller IC.

The MAX3735A provides transmit-disable control, a single-point latched transmit-failure monitor output, photocurrent monitoring, and bias-current monitoring to indicate when the APC loop is unable to maintain the average optical power.

The MAX3735A is available in a 4mm x 4mm TQFN package and operates over the extended temperature range of -40°C to +85°C.

Applications

* 1G/2G Fibre Channel SFF/SFP Optical Transceiver Modules * Gigabit Ethernet SFF/SFP Transceiver Modules * Multirate OC-3 to OC-48 FEC SFF/SFP Transceiver Modules

* Fully Compliant with SFP and SFF-8472 MSAs

* Programmable Modulation Current from 10mA to 60mA (DC-Coupled)

* Programmable Modulation Current from 10mA to 85mA (AC-Coupled)

* Programmable Bias Current from 1mA to 100mA

* Edge Transition Times <51ps

* 27mA (typ) Power-Supply Current

* Multirate 155Mbps to 2.7Gbps Operation

* Automatic Average Power Control

* On-Chip Pullup Resistor for TXDisable

* 24-Pin 4mm x 4mm QFN package