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ADS1298ECGFE-PDK: DVDD Current

Chris Newman
Prodigy 10 points
Part Number: ADS1298ECGFE-PDK
Other Parts Discussed in Thread: ADS1298

Hi,

What is the expected DVDD current on the ADS1298ECGFE evaluation board when configured for 3.3V operation using JP24?

  • When the PWDN jumper (JP5) is attached, I measure DVDD = 20.6 mA & AVDD  = 4.98 mA
  • When the PWDN  jumper is removed, I measure DVDD = 20.5 mA & AVDD  = 1.26 mA

The DVDD current is well outside the value listed in the ADS1298 electrical characteristics. It is always measures high regardless of the operational state of the device.

Other than this the device appears to be fully functional.

What would be the cause of the high current?

Thanks

-Chris

  • 0
    TI__Genius 11550 points

    Hi Chris,

    Welcome to the E2E forum !!

    The high current consumption is from the on-board clock oscillator. The external oscillator included on the EVM is powered by the DVDD supply, which is the same supply as the ADS1298. The EVM, by default, is shipped with the external oscillator enable. You can disable the on-board clock oscillator by setting the J19 jumper to position 2-3 and check the DVDD current consumption.

    Thanks

    -TC

  • 0 in reply to TCT
    Prodigy 10 points

    Hi TC,

    Thanks for your response!

    I forgot to mention in my original post that I have already disabled oscillator using J19. When the oscillator is enabled the DVDD current jumps up to 20.7mA.

    I also checked the current when I switch DVDD to 1.8V while the oscillator is disabled.

    • PWDN jumper fitted - DVDD = 7.03mA,  AVDD = 1.34 mA
    • PWDN jumper removed- DVDD = 7.04mA,  AVDD =  5.05 mA

    Thanks

    -Chris

  • 0 in reply to Chris Newman
    TI__Genius 11550 points

    Hi Chris,

    Thanks for the clarification. 

    I do not see such a high DVDD current (~7mA) on the EVM with the external clock disable. Please let me confirm the power consumption number on the EVM and get back to you.

    Thanks

    -TC