Laser driver with automatic power and modulation control

Nov. 2, 2001--Maxim Integrated Products has introduces the MAX3865, a low-power laser driver designed to modulate laser diodes at speeds up to 2.5 Gbits/sec while maintaining constant optical power output and extinction ratio over the lifetime and temperature.

Maxim Integrated Products has introduces the MAX3865, a low-power laser driver designed to modulate laser diodes at speeds up to 2.5 Gbits/sec while maintaining constant optical power output and extinction ratio over the lifetime and temperature.

Programmable output levels are set through externally adjustable bias and modulation currents. Two feedback loops can be enabled to control optical power. The automatic power control (APC) loop maintains average optical power. The automatic modulation control (AMC) loop maintains constant modulation through the synchronous detection of a small pilot tone added to the modulation current. Programming the device may be accomplished with all passive support circuitry. The laser driver is fabricated with Maxim�s in-house second-generation SiGe process.

The MAX3865 has differential clock and data input signals with on-chip 50 ohms termination resistors. Inputs can be configured for CML or other high-speed logic. An input data-retiming latch is available to reject input pattern-dependent jitter if a clock signal is available. The driver can modulate laser diodes at amplitudes up to 60mAp-p. With typical edge speeds of 110ps, the MAX3865 can supply a bias current up to 100mA. Incorrect response of the laser diode to modulation and bias is indicated by the FAIL pin. Early detection of laser degradation is available from the bias modulation current monitors included in the MAX3865.

The MAX3865 is available as an 80mil x 120mil die or a 32-pin QFN package with exposed pad. It operates from a +3.3V supply over a -40 degrees Celsius to +85 degrees Celsius temperature range. Prices start at $21.95 (In quantities of 1,000 or more). Evaluation kits are available.

For more information, visit www.maxim-ic.com.

More in Electronics