ADS8681: Initial conversion right after power up

Oba

Part Number: ADS8681

Tool/software:

Hello,

Right after power up, if the default register setting is OK, does just rising edge of CONVST/!CS start the conversion even though no SCLK is received before the rising edge like the below?

Regards,
Oba

3 months ago

0 Tom Hendrick 3 months ago

TI__Guru**** 181001 points

Hi Oba,

The rising edge of CONVST opens the sample and hold switch, locking whatever voltage is on the sample/hold cap for the conversion process. The conversion clock is internal - see 7.4.2.3 of the datasheet.

0 Oba 3 months ago in reply to Tom Hendrick

TI__Genius 17335 points

Hello Tom,

So right after powering up, if there is eough CONVST low period for ACQ before the rising edge of CONVST, the conversion should be valid.
No SCLK is needed for it. Correct?

Regards,
Satoshi Obata

+1 Tom Hendrick 3 months ago in reply to Oba

TI__Guru**** 181001 points

You only need SCLK to clock out the conversion results. Assuming the analog input is fully settled and there is adequate acquisition time, the first conversion would be valid.

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ADS8681: Initial conversion right after power up