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ADS8685: GPO and shunt Resistor for current Signals

Salacia
Prodigy 80 points
Part Number: ADS8685


Hello,

i have a question about the GPO on Pin 14. Is it possible to connect a 500Ohm shunt resistor between AIN_P and the GPO to measure current Signals (e.g. 4-20mA) as well? For normal voltage Signals (e.g. 0-10V) i would set the Bits 9-8 of SDO_CTL_REG to 00b = "SDO-1 is always tri-stated". In case of current Signals i would set the same Bits to 10b = "SDO-1 functions as GPO" and the Bit 12 of the same Register to 0b. I'm assuming that the GPO has a push pull function and the shunt resistor is connected to GND in this case.

I would also like to know if the maximum GPO current consumption of 20mA would cause demage to the ADC.

Thank you!

  • 0
    TI__Mastermind 46215 points

    Hi Salacia,

    GPO Pin 14 is a digital output pin, it should not be used for any analog input signal, this voltage on this GPO pin is limited between -0.3V~DVDD+0.3V as an output pin  Also, any input or output current on ADC's pins should be limited between -10mA~10mA except power supplies.

    Thanks.

    Regards,

    Dale