270Mbps SFP LED Driver

The MAX3967A is a programmable LED driver for fiber optic transmitters operating at data rates up to 270Mbps. The circuit contains a high-speed current driver with programmable temperature coefficient (tempco), adjustments for LED prebias voltage, and a disable feature. The circuit accepts PECL data inputs, and operates from a single +2.97V to +5.5V power supply.

The SFP LED driver can switch up to 100mA into typical high-speed light-emitting diodes. As temperature increases, the device's modulation current increases with a tempco that is programmable from 2500ppm/°C to 12,000ppm/°C. The modulation current is programmed with a single external resistor.

The MAX3967A's LED prebias voltage is programmable from 400mV to 925mV. The prebias circuit produces peaking current, which improves the LED switching speed.

Complementary current outputs help to maintain a constant supply current, reducing EMI and supply noise generated by the transmitter module. The MAX3967A is available in die form, or in a 4mm x 4mm, 24-pin thin QFN package.

Applications

* 155Mbps LAN ATM Transceivers * ESCON Receivers * Fast Ethernet/FDDI * Multimode LED Transmitters * SFP Transceivers