GPIO in high impedance - low power

[julienh]

Hi,

I use an NRF52840 in my product. The NRF52 is interfaced with an external module in UART.
The NRF52840 is always powered by the battery using the different power mode to save battery. Due to high leakage current on the external module, we need a load switch on the external to avoid draining the battery in sleep mode. They recommend to use a switch on the UART interface to put all the GPIO in Hi-z to avoid leakage and not forcing a GPIO which is not powered.

It's a consumer product and if I can save 0.2$ by not adding an external IC to put all the interface in Hi-Z, that would be good.

Is that a valid solution to reconfigure all the GPIO of the NRF52 in default configuration so they will be in Hi-z before disabling the power of the external module. Could you confirm that it's a true high-Z and that we will not have any leakage on the I/O?

Thank you

[Einar Thorsrud]

Hi,

Is that a valid solution to reconfigure all the GPIO of the NRF52 in default configuration so they will be in Hi-z before disabling the power of the external module

Yes, that is the way to do it. The default state is disconnected input, which is high impedance.

Could you confirm that it's a true high-Z and that we will not have any leakage on the I/O?

Yes. See this post.