ADS8422 incorrect data at particular voltage range

NITIN DATE

Other Parts Discussed in Thread: ADS8422

we are capturing data from ADS8422, simple sine wave is feed to capature from 0 to 3.3V level,we observed at 150mV to 450mV step sizes are changing. but they are not sinusoidal as per input , refer attached excel file for details, and waveform captured on oscilloscope at same time. Please suggest us the solution for this issue as it is coming in all boards in this particular region.ADS8422_range issue.xlsx

over 9 years ago

0 Shridhar%20More over 9 years ago

TI__Expert 8945 points

Hello Nitin,Thanks for choosing TI.
I will need more data to identify the possible cause for this failure.
Please help me with schematic of the ADC & the input signal chain.
Also, please feed a DC signal around the input voltage levels where you are observing issue. Capture multiple samples & share the captured results.
I will get back to you if I need any other data.Thanks & Regards,Shridhar.

0 NITIN DATE over 9 years ago in reply to Shridhar%20More

Prodigy 25 points

Hi Shridhar ,

Thanks for reply refer attached schematic and capture data in application FYI, Input is video signal to amplifier and o/p of amplifier given to ADC, you can see at 0.25 DC level there are pulses coming in between, where as if DC level increase upto 1V then no issue.

Best Regards

Nitin Date

spectum with dc voltage.docx

0 Shridhar%20More over 9 years ago in reply to NITIN DATE

TI__Expert 8945 points

Hello Nitin,

Apologies for the delay.

Unfortunately, the uploaded schematic link is not working & I am unable to download the schematic.

I have sent a friend request to you. Please accept the same & share the schematic over email. I will get back to you.

Thanks & Regards,
Shridhar.

0 Shridhar%20More over 9 years ago in reply to Shridhar%20More

TI__Expert 8945 points

Hello Nitin,

The conversation will now continue offline.

Thanks & Regards,
Shridhar.

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ADS8422 incorrect data at particular voltage range