• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 46 subscribers
  • Views 236 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

ADS112C04: ADS112C04 not working (burning)

ADS112C04: Could ADS112C04 be used in two channel RTDs applications?

Matt Qi
Intellectual 2590 points
Part Number: ADS112C04
Other Parts Discussed in Thread: ADS1147

Hi team,

We have a question about the ADS112C04:

Could ADS112C04 be used for two channels RTDs.

In the datasheet, the typical application is just for 1 channel RTD.

If we want to use 1 chip to test 2 channel RTD, the sampling rate may not higher than 20 sps (means that we will test 2 channel data in 50ms).

Our thought is we use the AIN0 & AIN1 test 1 channel RTD, and AIN2 &AIN3 test another channel RTD, the 2 channel RTD share one Rref,  but sample in different time.

 It works in ADS1147, please help to confirm whether it also works in ASD112C04. The external connection with the RTD and pins are following:

Best Regards,

Matt.

  • 0
    TI__Expert 6220 points

    Hi Matt.

    Yes, it is possible to do two separate RTDs with a single chip, but it is only possible with 2-wire RTD configuration, and not with 3-wire RTD configuration as shown in your first image. 

    An example on how to implement this can be found in our app note A Basic Guide to RTD Measurements (Rev. A) (ti.com): 

    Since the IDAC current would be coming out of the AIN0 pin the input filters would not be able to be implemented due to the voltage drop across the input filter resistor. 

    Also, special consideration must be taken when designing a circuit like this to make sure you don't violate the IDACs compliance voltage.

    Best Regards,

    Angel