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

4 Summary

Light Scattered by particles is dependent on particle’s physical parameters like shape, size and refractive index. Optical PM Sensors uses light scattered by particles to estimate the PM2.5 and PM10 concentration in air. The light scattered by the particles is converted into an electrical signal using analog front end. This application note showed a method to design a single operational amplifier based analog front end for PM sensors using OPA607. The report discussed in detail the calculations of signal chain parameters like bandwidth, noise and sampling the output voltage using a SAR ADC.