ADS7828: problem with ADC ADS7828

Shlomi Yehezkia

Part Number: ADS7828

Hi Team,

I am working with this configuration with the slow ADC (attached schematic).

Unfortunately, I learn that every time that I doing power up, I receive wrong value for the 1^st converting data, after that from the 2^nd converting I receive the right value. All of that without any connection to the number of channel (CH0 – CH7) that I start with.

Please advise what to do.

Thanks,

Shlomi

over 7 years ago

0 Abhijeet Godbole over 7 years ago

TI__Expert 5575 points

Hi Shlomi

Can you please monitor AVDD, Vinput and VREF after power up. How fast after power up are you reading ADC result.
Are you using internal reference or external reference. Please check if reference voltage is settled to final value after power up or not.
Also I do not see any decoupling capacitor on REFIN/OUT pin. Please keep provision for 0.1uF capacitor close to REFIN/OUT pin.

Thanks & Regards
Abhijeet

0 Shlomi Yehezkia over 7 years ago in reply to Abhijeet Godbole

Mastermind 6150 points

Hi Abhijeet,

While tracking your question, I solve the problem ... (I miss the internal reference turn-on sequence)

Thanks a lot for your help,

Shlomi

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ADS7828: problem with ADC ADS7828