NRF905 external PA

[Edriano Carlos Araujo]

Hello all,

I have been using nrf905 for about 5 years without problems. now I would like to ask if is there any way to use an external PA? I am not a RF engineer and i am not sure if it is a good idea.

thanks in advance.

[ketiljo]

Connecting the PA is quite straight forward. You need two RF switches that are used to switch in the PA in TX mode and bypass it in RX mode. All this is placed after the matching network so you will have a 50 ohm system the switches and PA's input and output.

VDD_PA can be tapped and buffered to control the switches and the PA it selves. VDD_PA goes high (1.8v) only when the TX is active.

Most RF switches have a DC voltage on the input and output pins, so make sure you are using DC block capacitors where appropriate. Refer to the manufacturers datasheet.