ADS1191: Datasheets explanation regarding data read out

Part Number: ADS1191
Other Parts Discussed in Thread: ADS1192


We are working with ADS 1191 (One Channels); we have NOT sw powered down channel 2 since, to our understanding, it is NOT present into the ADS 1191.

In this condition we were expecting to read 0x0000 on the SPI 16 bits related to channel 2; however we are reading 0xC000 or 0xC040 or 0xC060 on different boards / different power cycle

Could you help us to understand why? (Note: in our design pin 5 and 6 are just unconnected (floating))

What should we expect if we replace ADS 1191 with ADS 1192 under the same condition?

Thanks in advance



  • Hi MD,

      Let me understand your clearly. You are trying to work with ADS1191, correct?

      May I ask what makes you need to replace the ADS1192 to ADS1191 and what was the original part# and package you were using?

      Feel free to let me know if you want to bring this discussion to private.

      May I ask which register address are you trying to read? Were you able to read Address = 00h ID Control Register correctly according to ADS1191 data sheet page 36?

      What is your Vref voltage and how is your Channel 1 reading e.g. use Channel1 to read the Test Signal?

      Pin 5 and 6 are inputs for Channel 2 for ADS1192, which can be ignored for ADS1191. Floating means the voltage could be any undetermined values at any moment. Would you try to connect those Pin5 and 6 to GND and read again?


    Would it be possible for your to probe and capture the following on the scope?

      In the meantime, let me discuss with other engineers to see how the DOUT should be for ADS1191 device and how to treat CH2 pins and DOUT CH2 segment/block.


  • This ticket is being discussed in the private chat & discussion.

  • Hi,
    Since I did not hear back from you, I believe my suggestions answered your questions.
    I will close this post and if you have any pending questions, feel free to post them here or open a new thread.
    Thanks and have a great day!