ADS131A04: ADS131A04 application question

Sulyn ZHANG

Part Number: ADS131A04

Team,

My customer now is using ADS131A04 in new project, to optimize the performance and considering customer's real situation, I have several questions want to double check with you:

Sample rate was set to 16ksps but customer can't well suited R76 and C91.

The question are:

1. What is the recommended R76 and C91 here?

2. Now they use R76=100ohm and for C91, if they use NP0 cap, they only have 1nF for 0805 package now, is this ok?

3. For C91, If NP0 is not must have, when customer do high and low temp test they will have big phase shift, do we have solution to solve this phase shift during

temp test?

Best regards,

Sulyn

over 7 years ago

0 Tom Hendrick over 7 years ago

TI__Guru**** 180791 points

Hi Sulyn,

Send me a note with a little more detail on the sensor you are connecting to the ADS131A04 and the input signal you are trying to capture and we can discuss this further. In general though, the cutoff of the differential filter should be ~10X your data rate to avoid aliasing. Good quality capacitors are critical for use with any data converter. Post processing of the signal can help, but you would ideally want to avoid issues before you digitize the signal.

0 Sulyn ZHANG over 7 years ago in reply to Tom Hendrick

TI__Expert 8700 points

Tom,

Thanks for the support. For your question:

1. The application is relay protection and input signal is from PT or CT sensor.

2. For the input signal, the input frequency is up to 1.6kHz, that is 50Hz and maximum 32 harmonics;

So based on above information and customer can only use 1nF NP0 cap, can you help recommend the Resistor used here? Thanks.

Best regards,

Sulyn

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ADS131A04: ADS131A04 application question