ADI ADN2830ACPZ32

The ADN2830 provides closed-loop control of the average optical power of a continuous-wave (CW) laser diode (LD) after the initial factory settings. The control loop adjusts the laser IBIAS to maintain a constant back-facet monitor photodiode (MPD) current, thereby maintaining a constant laser optical power. An external PSET resistor is adjusted during factory settings to set the desired optical power. RPSET is set to 1.23/I_AV, where I_AV is the MPD current corresponding to the desired optical power. Programmable alarms are provided for laser failure (end of life) and laser degradation (imminent failure). To monitor the MPD current, the MPD can be connected to the IMPD pin. In this case, the MPD current is mirrored to the IMPDMON pin to provide monitoring and internally mirrored to the PSET pin to close the control loop. By using IBMON instead of the MPD connected to PSET to close the feedback, the device is configured to control a constant current in the laser rather than a constant optical output power.