ADC128S102: Looking at strange behavior with the DOUT line

Hi Jeff,

Thank you for your question! That is strange. A few questions that would help me better understand your issue:

1. Could you please share your schematic?
2. What is the state of the /CS signal?
3. Are you seeing this result continuously?
4. Does power cycling the part change its behavior?

Best,

Samiha

I am

I am wondering if the 100 ohm series resistor might be a problem.

CS is asserted during this time.

I do see different things when I power the board back on.

Thanks,

Jeff

I should add there are two of these circuits and the DOUT is connected together but the CS for the other one is not being asserted

Hi Jeff,

Thanks for providing those details. How does the behavior change after you power cycle?

I wonder if the second DOUT is interfering and causing this behavior. DOUT is in high impedance state when /CS is high so the second DOUT would be floating, potentially causing issues with the first DOUT reading. Could you disconnect the two DOUTs and then probe them separately? For the scope-shot you provided, what were the inputs used/output expected?

Best,

Samiha

I will do as you suggested and isolate the DOUTs. Might not be till next week as my technician is out.

The scope-shot I provided, I didn't expect DOUT to toggle at the beginning since its in the area that the part says should be sending 0s and not data yet.

Thanks!

Sounds good! I will close the thread for now. When you respond again, it will reopen!

Best,

Samiha