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

2.3.1 Minimum Current Calculations

The minimum measurable current is the photocurrent which generates an output voltage equal to the LSB of ADC. Thus, expression for minimum current is given by,

Equation 6. Iin_min= Vref2N x 1Rf= 3210 x 160 x 106=50 pA