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PGA305EVM-034: ADC & DAC Calibration

Part Number: PGA305EVM-034

I don't understand how ADC & DAC  calibration works. What's the difference between DAC an I2C output calibration? What DAC codes and CalcCode mean? In which pin is read the read_V (Since the voltage read from the pressure sensor can't be larger than 2.5 and one of the predefined desired_V values is 4,00V)?

  • Hello Ricardo,

    There are 2 different output modes for the PGA305, a digital I2C output or the DAC output (voltage or current mode). You can calibrate the output at different temperatures for either of those modes.

    The DAC code is the code that is written to the DAC for the calibration procedure. You write that code to the DAC, measure the analog output, and put that in the Read_V column. You input the desired output (Desired_V) for that point (this will correspond to the ADC calibration points) and once the whole column is populated you can click the Calculate Code to calculate the adjusted DAC codes that provide the exact desired output.

    This is all calibration of the DAC, and the DAC voltage output can go up to 10V, so 4V is within the output range.

    Regards,
  • Thanks for your reply. How do I choose the most appropriate DAC code? Besides that, I have another problem, when I try to change the Read_V and Desired_V and press enter the value inserted becomes 0. I can only change the values in the DAC Codes column.
  • Hello,

    You can choose the DAC code to output a value close to your desired output. This will depend on the gain value that you have selected.

    You should be able to change the desired_V values at any time. To change the Read_V values you will have to click on the DAC Code cell to the left of it, and click the "Write DAC Code" button at the bottom. This will highlight the Read_V cell and allow you to change the value.

    Regards,