ADL5317 Datasheet | Analog Devices

Features Accurately sets avalanche photodiode (APD) bias voltage Wide bias range from 6 V to 75 V 3 V-patible control interface Monitors photodiode current (5:1 ratio) over six decades Linearity 0.25% from 10 n A to 1 m A, 0.5% from 5 n A to 5 m A Overcurrent protection and overtemperature shutdown Miniature 16-lead chip scale package (LFCSP 3 mm × 3 mm) FUNCTIONAL BLOCK DIAGRAM 16 15 14 13 M FALT OVERCURRENT PROTECTION THERMAL PROTECTION CURRENT MIRROR 5:1 NC 12 APPLICATIONS Optical power monitoring and biasing in APD systems Wide dynamic range voltage sourcing and current monitoring in high voltage systems VSET 30 × VSET IPDM 29 × R IAPD 5 VPLV VPHV VPHV R IAPD VCLH NC 10 GARD VAPD GARD 9 Figure 1. GENERAL DESCRIPTION The ADL5317 is a high voltage, wide dynamic range, biasing and current monitoring device optimized for use with avalanche photodiodes. When used with a stable high voltage supply (up to 80 V), the bias voltage at the VAPD pin can be varied from 6 V to 75 V using the 3 V-patible VSET pin. The current sourced from the VAPD pin over a range of 5 n A to 5 m A is accurately mirrored with an attenuation of 5 and sourced from the IPDM monitor output. In a typical application, the monitor output drives a current input logarithmic amplifier to produce an output representing the optical power incident upon the photodiode. The photodiode anode can be connected to a high speed transimpedance amplifier for the extraction of the data stream. A signal of 0.2 V to 2.5 V with respect to ground applied at the VSET pin is amplified by a fixed gain of 30 to produce the 6 V to 75 V bias at Pin VAPD. The accuracy of the bias control interface of the ADL5317 allows for straightforward calibration, thereby maintaining a constant avalanche multiplication factor of the photodiode over temperature. The current monitor output, IPDM, maintains its high linearity vs. photodiode current over the full range of APD bias voltage. The...