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.

TMDSCNCD28388D: Measuring 100kOhm pull-down at analog input of control-card

Part Number: TMDSCNCD28388D

Hello everyone

I am using the TMDSCNCD28388D control card and I have run into an issue related to the input impedance of the ADC A0 channel.

On my power electronic board, I am using six ADC channels in single ended mode to measure signals from identical sensors in range [0V,3V].

5 of the channels work properly but I noticed some pull-down effect on Channel ADCA0, e.g. the analog signal coming in at this position seems to be pulled down to ground somehow.

After some debugging I noticed that when I measure the resistance at the corresponding pin of the control-card (pin No. 9) I measure around 100kOhm (during the measurement, I removed the control card from the socket, e.g. the issue seems to be on the control card and not on the board it is connected to).

This node is essentially only connected to the microcontroller Pad U1 and an ESD protection array (TPD4E001QDBVRQ1), see also image below:

Is it possible that the TPD4E001QDBVRQ1 is the cause of this issue and should I replace it.