CC2650: CC2650 - INPUT_EN NOPULL on analog capable pins yields ~70uA power draw

Craig Hesling

Part Number: CC2650

Does anyone know why simply enabling the input mode with nopull on IOID23 through IOID30 (analog capable pins) yields about 70uA power draw per pin?

If I enable pull-up or pull-down, the power draw goes away.

I am using a clean shutdown example on the CC2650 Launchpad with nothing connected to the IO pins.
I am configuring the default pin behavior in the IO init table, BoardGpioInitTable.
I have removed the Flash and can achieve 90nA if I don't configure the analog capable pins.

Best,

Craig

over 7 years ago

0 Fredrik K over 7 years ago

TI__Guru** 106705 points

Hi Craig,

Are you pulling the input pin either 0 V or VDD externally? If the input floats with no pull the input buffer will draw excessive current as you are observing.

Cheers,
Fredrik

0 Craig Hesling over 7 years ago in reply to Fredrik K

Prodigy 60 points

Nope, that's the weird thing. I have confirmed this behavior on the Launchpad with nothing connected and on my own design with nothing connected to any of these pins.

Seems like some sort of metastable thing, since touching the pins momentarily brings the power down to nA.

Thanks,

Craig

0 Fredrik K over 7 years ago in reply to Craig Hesling

TI__Guru** 106705 points

Hi Craig,

If you have nothing connected to the pin and no internal pull enabled what you observer is not surprising. A logic level input buffer requires being pulled to either 0 V or VDD one way or another. If the input is floating it will result in excessive current consumption.

Cheers,
Fredrik

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CC2650: CC2650 - INPUT_EN NOPULL on analog capable pins yields ~70uA power draw