RE: Use the 50-Ohm Antenna as voltage input.

Kazi Afroza Sultana — Tue, 13 May 2025 08:18:12 GMT

Hello,

1: Is the idea mentioned above feasible?

2: There will be some voltage on the ANT pin while 5V input from antenna pin.
What is the maximum voltage to the ANT pin without affecting the function or causing damage?

4. How about if we change the charging voltage from 5V to 2.7V, i.e. we use +2.7V input instead, is it much better and feasible?

The idea is not feasible as ANT pin is designed for RF signals and should be connected to a 50-ohm antenna through properly matching RF network. The ANT pin is not designed to work on DC power input or battery charging current.

General PCB design guidelines for nRF52 series

3. Or is it possible to isolate the ANT pins if we use the antenna pin as 5V input by GPIO configuration in the firmware?
so that we can isolate the ANT pins or set it to other usage for protection.

As I mentioned in my previous reply, ANT pin is only dedicated for RF performance. So, it can not be reconfigured or isolated via firmware. It is not possible to multiplexed with GPIO unlike NFCT pin. You can use NFC pin as GPIO pin with some modification in hardware and software.

RE: Use the 50-Ohm Antenna as voltage input.

WFKwok — Tue, 13 May 2025 02:27:07 GMT

Some more info, we do plan to add an RF switch to isolate the charging path while not in BLE usage.
And we will apply 2.7V instead of 5V for battery charging.
Just not sure whether the RF switch can stand for the load 2.7V with 20mA.
So is it still feasible to achieve the idea with an RF switch?