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Question about CN0359 (ADC, signal line connection)

Pins 38 and 40 of ADUCM360 shown in the reference circuit diagram of CN0359 are connected to the "AD8253_A0" signal.

   1) I would like to ask what is the meaning of connecting pins 38 and 40 of ADUCM360 in the above "AD8253_A0" signal.


   2) I don't use ADUCM360, I want to use a different processor. The processor I'm going to use doesn't have a 24bit ADC.

       Please recommend your company's ADC that can be used as an external ADC (using I2C communication) that can be used instead of the ADC inside the ADUCM360.

We ask for your help.

modify to I2C interface (Ext ADC)
[edited by: Justin.Jung at 6:52 AM (GMT -5) on 14 Jan 2022]
Parents Reply Children on Jan 17, 2022 9:18 AM in reply to Justin.Jung

So there is a 4-channel version, the AD7124-4

  • I have an additional question to ask in addition to your answer.

    1) Why use PWMSYNC?
    2) My CPU doesn't have PWMSYNC function, so if I don't use this function, will there be any problem in measuring the conductivity?

    Thank you rogueC for your support.

  • Hi Justin,

    Sorry for the late reply. I missed your additional question.

    1. The CN0359 continually does sample-and-hold of the positive and negative voltage and current through the conductivity probe. When the gain is changed, it is possible that one or more of the 4 measured values were taken from the previous gain setting which will mess up the computed conductivity value at that point. PWMSYNC ensures that this does not happen.

    2. An alternative to this would be to disregard or even stop sampling when changing gain and restart the pwm signals once finished.

    Best Regards,