AD8304ARUZ

Overview

The AD8304ARUZ is a monolithic logarithmic converter optimized for fiber optic photodiode interfacing. It provides an exceptionally large dynamic range of 160 dB, spanning from 100 pA to 10 mA input current. The device features a laser-trimmed logarithmic slope of 10 mV/dB at the VLOG pin and a basic intercept at 100 pA. Operating on a single supply voltage between 3.0 V and 5.5 V, it draws approximately 4.5 mA of quiescent current. The output buffer offers a bandwidth of 10 MHz and supports low-pass filtering configurations.

Feature Summary

• Optimized for fiber optic photodiode interfacing with adaptive biasing to reduce dark current at low light levels
• Features precise laser trimming for accurate logarithmic scaling and temperature stability across the operating range
• Includes a rail-to-rail output buffer capable of driving loads and implementing multipole low-pass filters

Applications

• High accuracy optical power measurement in fiber optic systems
• Wide range baseband log compression
• Versatile detector for automatic power control (APC) loops

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm packaging options such as tube or reel variants. Ensure compatibility with the required temperature range and package style before procurement. Cross-reference the part number with authorized distributors to confirm current availability status and lead times.

Selection Notes

Select this component when a wide dynamic range logarithmic conversion is required for low-frequency signals. Consider the 10 mV/dB default slope and 100 pA intercept for standard applications. Evaluate the need for external slope adjustment resistors if using lower supply voltages or requiring specific output spans. Verify that the 10 MHz buffer bandwidth meets the signal processing requirements.

Part Context

The AD8304 belongs to Analog Devices' family of translinear logarithmic amplifiers designed for precision measurement. Unlike RF detectors, this device utilizes bipolar transistor characteristics to convert input current directly into a logarithmic voltage. It is distinct from other series members by its specific optimization for DC to low-frequency photodiode interfaces rather than high-frequency RF envelope detection.

Replacement Considerations

No public confirmed substitute part numbers are available.