ADS1282: Is it okay to partially power down the ADC (AVDD/AVSS off, DVDD on)

Andrew Kinmont

Part Number: ADS1282

Is it acceptable to power off the analogue supplies (AVDD and AVSS), but keep the digital supply (DVDD) active? I appreciate that we will need to ensure that none of the analogue inputs are driven in this mode, at least.

In this mode, we would also disable the clock input, and hold RESET pin low.

We are looking at simplifying our design, so want to remove the components that are currently employed to isolate the digital I/O pins when all of the power supplies are switched off.

Thanks,

Andrew

over 6 years ago

0 Christopher Hall over 6 years ago

TI__Mastermind 44680 points

Hi Andrew,

If you are careful not to apply signals to any of the analog inputs (or at least current limit these signals to <10mA), then it shouldn't be an issue to power down the analog supply while leaving DVDD powered.

The only other caution I would give is to take care to pull AVDD and AVSS to ground (hopefully your supply LDO already does this. See www.baldengineer.com/5-ldo-regulator-considerations.html) and leave them off long enough for the supply decoupling capacitors on these supplies to fully discharge. I have seen some funny effects occur on other devices when powering devices from a partially powered state.

0 Andrew Kinmont over 6 years ago in reply to Christopher Hall

Prodigy 20 points

Hi Chris,

Thanks for the response.

I also appreciate the advice about the LDO pull-down. This is something that I will look in to.

Regards,

Andrew

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ADS1282: Is it okay to partially power down the ADC (AVDD/AVSS off, DVDD on)