ADN2840

2.5 Gbps Laser Diode Driver with Dual-Loop Control

The ADN2840 is a 2.5 Gbps laser diode driver that utilizes a unique control algorithm to manage both average power and extinction ratio after initial factory set-up. Average monitor photo diode current is used to control Ibias and consequently average power. Modulation current is changed linearly with slope efficiency. Any changes in the laser threshold current or slope efficiency are thus compensated for, minimizing laser characterization efforts.

2.5 Gbps Data Rate (100 ps per division), 40 mA Modulation Current into 25 Ohm Load, 20 mA Bias Current, PRBS31

Other Features:

• 80 mA modulation current and 100 mA bias current drive capability
• 80 ps typical rise-time at 2.5 Gbps operation
• Dual monitor photodiode inputs for WDM wavelength control purposes
• IDTONE input for wavelength identification or supervisory channels
• Laser fail/laser degrade alarms
• Automatic laser shutdown (ALS)
• Full current parameter monitoring

The ADN2840 uses three variable resistors to set average optical power, extinction ratio and the bias current at which the FAIL alarm goes logic high. The DEGRADE alarm goes high at 95% of the FAIL alarm trip point.

This device can be used for DWDM dual MPD wavelength fixing, as well as SONET/SDH OC-48 and SDH STM-16 applications.

The ADN2840 operates from a single power supply at +5 V. It is packaged in a 48 pin TQFP-EP package.