REGOUT0 regulation issue in low power mode

RE: REGOUT0 regulation issue in low power mode

Jørgen Holmefjord — Wed, 04 Mar 2020 09:47:36 GMT

I'm not sure I understand this comment:

[quote user="David Costa Campos"]When the analog part is on and the MCU IO isn't configured, the MCU is waked up and the voltage drops to 2.5 V or 2.3V.[/quote]

If the GPIO is not configured, why do you expect a high voltage on it? Or do you see a voltage drop on other GPIOs?

The GPIO specifications have a minimum high output value of VDD-0.4V, meaning these numbers are within spec.

Is the analog part drawing a large current?

The GPIOs are by default high impedance (input buffer disconnected, no pull configuration).

RE: REGOUT0 regulation issue in low power mode

David Costa Campos — Fri, 28 Feb 2020 09:49:53 GMT

Hi Jørgen,

I am testing only with this code, the rest is commented.

I have done more testes and I found out that our subcontractor sent us the wrong revision on the schematics. An analog part of the schematics was missing. Sorry for the inconveniences.

So we had an analog part with an enable pin which was floating. This analog part generate a voltage between 0 to 1.5 V to P0.03 of the nRF52840 which wasn't configured.

When the analog part is on and the MCU IO isn't configured, the MCU is waked up and the voltage drops to 2.5 V or 2.3V.

But when the IO is configured in input mode, the voltage doesn't drop and stays at 2.7 V.

Is the IOs in high impedance mode when they aren't configured ?

I can't explain this voltage drop.

David

RE: REGOUT0 regulation issue in low power mode

Jørgen Holmefjord — Thu, 27 Feb 2020 16:32:03 GMT

Hi,

Are you testing with only this code, or is this extracted from a larger application? Have you tried reproducing this on a nRF52840 DK, or without the filter?

Can you give exact current measurements before and after the current increases?

Best regards,
Jørgen