ADS1298: ADS1298 ADVDD curent consumption

Hi,

Have you changed anything on the ADS1299 EVM and the MMB0 board?

It's suggested to reset every jumper shunts to factory default.
The way you show on the picture is to measure the DVDD not for AVDD.
What voltage do you want/desire to use and measure for the DVDD?

Make sure to document and take pictures what you have changed.

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Did you remove the jumper shunt to put ampere meter in series?

either 80mA or 100mA measured from JP24 are too high.

around twenty-ish  mA should be reasonable.

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Please make sure to follow the user guide, especially the Power Supply section, to provide correct powers and check all the power rails. 

Thanks.

Hi ChienChun,

    Thanks for you reply!

Have you changed anything on the ADS1299 EVM and the MMB0 board?---I didn't change anything on the ADS1298EVM and the MMB0 board.

It's suggested to reset every jumper shunts to factory default.
The way you show on the picture is to measure the DVDD not for AVDD.
What voltage do you want/desire to use and measure for the DVDD?----I measuered the DVDD, AVDD and AVSS Separately with a DMM as the picture below.

Make sure to document and take pictures what you have changed.

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Did you remove the jumper shunt to put ampere meter in series?----Yes!

either 80mA or 100mA measured from JP24 are too high.

around twenty-ish  mA should be reasonable.-----I checked the DVDD on schematic it connected to OSC and ADS1298.The OSC current is about 10mA max in datasheet.

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Thanks a lot!

HI,

Would you use some better measurement tool? e.g. sharp needle tip or test lead/wire grabber. The way of measuring shown in the picture may cause accidently short to unwanted pin and unstable.

Make sure the amp meter is really in series with the DVDD.

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I think you are right,

there is no independent and sole way to only measure the current that goes from DVDD rail to the DVDD pins of ADS on the EVM as it's shared by several other pins components.

there is no independent and sole way to only measure the current that goes from AVDD rail to the AVDD pins of ADS on the EVM as it's shared by several other pins and components.

If the DVDD current measured is 80mA or more at and after power up without changing anything(i.e. everything default), that is too high.

Twenty-ish mA is a reasonable range across JP24 if select DVDD to be 3.3V even when acquiring at 8000SPS.

Please make sure all the voltage rails are correct by default.

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Thanks

Hi ChienChun,

Thanks a lot!

Would you use some better measurement tool? e.g. sharp needle tip or test lead/wire grabber. The way of measuring shown in the picture may cause accidently short to unwanted pin and unstable.

Make sure the amp meter is really in series with the DVDD.------I got a test grabber for measure the current of DVDD. And the DVDD current on the EVM board is still too high,but it worked well for get the internal suqare singal.

I found the DVDD come from the MMB0 board of a LDO TPS70302PWP that can output 1A current, So how to select a power supply for DVDD?

Could you verify the current if you have a EVM board on hand?

Thanks！

The LDO on MMB0 could supply upto 1A, but doesn't necessary mean it has/must always supply 1A. This is the limit.

If's only for ADS1298's DVDD only purpose, nothing else.  I think 200mA LDO should be more than sufficient. 

However, in your case, you may need to do more tests and measurement, but 200mA LDO should be a starting point.

Twenty-ish mA is a reasonable range across JP24 if select DVDD to be 3.3V when acquiring at 8000SPS.

Thanks