ADS7138-Q1: DVDD Power Consumption

McKenna Strambi

Part Number: ADS7138-Q1
Other Parts Discussed in Thread: ADS7038, ADS7138

Tool/software:

Hello expert,

Curious if any special internal circuits are powered from the DVDD pin on this device or if it's only IOs, since on another E2E I saw the power consumption is relatively negligible on this pin.

Thank you!

McKenna

2 days ago

0 Joel Meraz 2 days ago

TI__Genius 15150 points

Hi McKenna,

That is correct. All functional circuitry is powered by AVDD. DVDD just sets the IO voltage, essentially working as a level translator.

We specified typical I_DVDD for the ADS7038, which you can compare against. It is different between I2C and SPI, as the I2C lines are open-drain and pulled up.

Regards,

Joel

0 McKenna Strambi 1 day ago in reply to Joel Meraz

TI__Intellectual 1530 points

Hi Joel,

Where can I find the typical I_DVDD?

Best,

McKenna

0 Joel Meraz 1 day ago in reply to McKenna Strambi

TI__Genius 15150 points

Hi McKenna,

I'm referring here to the ADS7038 (SPI version of ADS7138). I_DVDD is found at the very bottom of section 6.5.

https://www.ti.com/lit/ds/symlink/ads7038.pdf

Regards,
Joel

0 McKenna Strambi 10 hours ago in reply to Joel Meraz

TI__Intellectual 1530 points

HI Joel,

Gotcha, thanks!

For another project, customer is using 2x ADS7138 to measure some thermistors on our MLB. These thermistors appear as a 100k impedance into the ADC but they are worried about introducing ADC error due to the high impedance. Can they manually control the ADC hold time to compensate for the high impedance?

Thank you!

McKenna

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ADS7138-Q1: DVDD Power Consumption