SNLA399 July   2022 OPA607

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction to Particulate Matter Sensors
    1. 1.1 Optical Particulate Matter Measurement Instruments
      1. 1.1.1 Photometer
      2. 1.1.2 Optical Particle Counter
        1. 1.1.2.1 Determination of Size and Concentration
          1. 1.1.2.1.1 Size
          2. 1.1.2.1.2 Concentration
    2. 1.2 Architecture of Optical PM Sensor
  4. 2Single Op Amp Based Analog Front End
    1. 2.1 Frequency Response
    2. 2.2 Noise
    3. 2.3 Data Acquisition
      1. 2.3.1 Minimum Current Calculations
      2. 2.3.2 Maximum Current Calculations
  5. 3Optimizing for Different Photodiode Currents
  6. 4Summary

Abstract

Particulate Matter (PM) refers to the solid and liquid particles suspended in air. PM Sensors are used to determine the PM2.5 and PM10 particle concentration in air. Optical PM sensors use light scattering principle to determine PM concentration in air. This application report looks into a single operational amplifier (Opamp) based analog front end (AFE) solution for Particulate Matter (PM) monitoring sensors. This application note discusses how the scattered light by the particles can be converted into an output voltage proportional to the intensity of light incident on the sensor. The voltage output can be processed using various algorithms to determine the concentration and size information.