SBOA601 January   2025 LOG200

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Critical Photodiode Specifications
  6. 3Interfacing the LOG200 With the Photosensor
    1. 3.1 Photodiode Connections
    2. 3.2 Photodiode Adaptive Biasing Current Output
  7. 4Optical Bench for Current Sensing Measurements
    1. 4.1 Transient Response with Photosensor
  8. 5Optical Power Measurements with the LOG200
  9. 6Error Sources and Uncalibrated Error Analysis
  10. 7Auxiliary Op Amp Circuits
    1. 7.1 Single-Ended to Differential Conversion Circuit
    2. 7.2 Sallen-Key Low-Pass Filter
  11. 8Summary
  12. 9References

Abstract

The LOG200 is a precision, high-speed, current-to-voltage logarithmic amplifier with integrated adaptive photodiode bias. The device is designed for current measurements across a wide dynamic range of 10pA to 10mA (180dB). It features a high-speed response spanning several decades of input current, allowing for a unique combination of fast transient response with high accuracy and logarithmic conformity.

This document provides guidelines, examples, and bench measurements, interfacing the LOG200 with photosensors for optical current sensing applications.