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How to configure by software that ads8688 input like current

Ernesto Ramirez
Prodigy 70 points
Other Parts Discussed in Thread: TIDA-01333


in the data sheet appears the section with the following text "and each channel can be configured as a current or voltage input with software configuration" i have  a 4-20 ma sensor , how to configure current input by software .

thanks in advanced

  • 0
    TI__Mastermind 35470 points

    Hi Emesto,

    The section 9.2.2 in page 55 of ADS8688 datasheet describes a reference design based on ADS8688 precision ADC(TIDU365, the web link in the datasheet for this design TIDA -00164 is directed an incorrect reference design TIDA-01333), this section mentions that this reference design can measure a voltage or current input including 4-20mA and 0-20mA. If we look at the section 5.1.2 and schematic of TIDU365, when measure 4-20mA current input signal, the host controller will control the switches(TLP3123) by TCA6408A to turn on a 200ohm shunt resistor on the input, converting the input current to 0-4V voltage signal to ADS8688 with a full-scale range of 5V. Please refer to below block diagram.

    ADS8688 is a precision 8-ch,16-bit ADC and only support unipolar or bipolar single-ended input voltage signal.

    Thanks.

    Best regards,

    Dale