ADS1262: IDAC rotation and temp senser solution support need

Hi Rock,

The IDAC rotation function is explained in section 9.3.8.5 of the ADS1262 datasheet. Basically, this is useful for 3-wire RTD measurements that use 2x IDACs, as it helps remove the error associated with the IDAC mismatch. If your customer is measuring a 2-wire or 4-wire RTD, or a 3-wire RTD with only 1x IDAC, then this feature will not be useful.

• You can learn more about RTD measurements using our RTD cookbook: https://www.ti.com/lit/an/sbaa275/sbaa275.pdf?ts=1608044056717&ref_url=https%253A%252F%252Fwww.google.com%252F
• You can learn more about IDAC mismatch with this 3 part article series (I have only linked to Part 1): https://www.embedded-computing.com/embedded-computing-design/excitation-current-mismatch-effects-in-three-wire-rtd-measurement-systems-part-1

In general the precision for an RTD system is largely dependent on the initial accuracy and drift of the reference resistor, which is external to the ADC. In other words, simply selecting a high accuracy ADC may not be helpful if the other system components are not also high accuracy.

If you would like to discuss this customer's specific case offline, please send me an email.

-Bryan