ADS1299-4: High operating current

Lumina Gui

Part Number: ADS1299-4
Other Parts Discussed in Thread: ADS1299

Hi TI Teams,

Our of our customer reported that the operating current was much higher than the datasheet current when they tested the power consumption of ADS1299-4. When all 4 channels are turned on the operating current is about 10mA (with the analog power supply is 5V and digital power supply is 3.3V) , while the datasheet has a current value of only about 5mA.

The operating current with all channels closed is about 2.5mA,each channel opened will increases the operating current by about 2mA, and the number of channels turned on increases the current by 2mA in equal proportions. They also do a lot of experiments but don't see any improvement in this operating current.

The schematic is as below:

The register setting as below:

Can you help to analyse the cause of the problem? Or can you give us some suggestion for this?

Thanks,

Kind Regards

over 1 year ago

0 ChienChun Yang over 1 year ago

TI__Mastermind 19815 points

Hi,

Do they test on a customer PCBA or the ADS1299 evaluation kit/board(EVM)?

And, do they use internal or external clock and what is the output data rate they use?

And, do they measure the current through AVDD only?

Thanks

0 ChienChun Yang over 1 year ago in reply to ChienChun Yang

TI__Mastermind 19815 points

Hi,

FYI, on an ADS1299EVM, the Iavdd current is measured around 7.8 to 8.5 mA, which could be close and within the the Iavdd range listed in datasheet -

The deviation is due to the fact that on the EVM, the AVDD does not only supply to the ADS, it also supplies to some other components, e.g. other OpAmps, resistors, etc, which draw some extra current.

Customer need to make sure solely/only measure the AVDD that supplies to ADS only.

Thanks

0 Lumina Gui over 1 year ago in reply to ChienChun Yang

Genius 3105 points

Hi Chienchun,

Thanks a lot. I have feed this back to our customer and they have find the problem.

Best Regards

0 ChienChun Yang over 1 year ago in reply to Lumina Gui

TI__Mastermind 19815 points

Hi,

Thanks. Wondering is it possible to share what problem they find if they don't mind?

Thanks

0 Lumina Gui over 1 year ago in reply to ChienChun Yang

Genius 3105 points

Hi ChienChun,

The customer feedback that they are measuring the input current at the 5V DC/DC, and due to the low efficiency of the DC/DC, the measured current value will be higher. We have suggested the customers to use the DC/DC with higher efficiency.

Thanks,

Best Regards

0 ChienChun Yang over 1 year ago in reply to Lumina Gui

TI__Mastermind 19815 points

Hi,

Thanks for letting me know.

Another suggestion might be considered is to please consider using LDO as DC/DC converter might be more noisy, which is not good for ADS1299 and/or any precision ADC's performance and/or SNR, etc...

Thanks

0 ChienChun Yang over 1 year ago in reply to ChienChun Yang

TI__Mastermind 19815 points

Closing this ticket as I haven't heard back from you.

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ADS1299-4: High operating current