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ADS1263: Simultaneously using pin for IDAC and Ref ADC

Alex Povov
Prodigy 10 points
Part Number: ADS1263
Hello,
 Now, Iam studing characteristics of the ADS1263, and am planning use this ADC in my current project.
 But I cant find the answer to one interesting question in datasheet. Unfortunately, I havent this ADC right now, and cant verify my question using hardware.
 For example, I want to connect reference resistor (for RTD) between AIN0 and AIN1, and switch those pins using internal multiplexers to inputs the Ref ADC1. Next, i want to connect IDAC1 to AIN0 for excitation RTD and reference resistor. In my opinion, Ref ADC1 and IDAC multiplexers are independent, and they can work with one pin simultaneously. Right? What problems will I get when trying to connect like this?
 Great thanks!
  • 0
    TI__Guru 51776 points

    Hi Alex,

    Yes, you can connect the IDACs to any input pin, even one you are using to measure the input channels or use as a VREF input. Table 5 in the ADS1263 datasheet gives a good summary of the pin functions.

    One thing to consider is that any filter resistors on those input channels or even trace impedances could cause an error on the reference or input signal measurements, since the current will cause an additional voltage drop across these components. We generally recommend using a separate pin to route the IDAC current through the reference resistor / RTD to avoid these issues.

    -Bryan