DRIVE AN POWER AMPLIFIER USING GPIO PIN

[SREEKUTTAN]

Hi Nordic.

Now I am working on a BLE smart card and am adding an external power amplifier. For low power consumption, i decided to give power only when I want PCB doesn't allow me to add more switching components so I think its a good idea to provide power via GPIOpins .my power amplifier is sky66111 and it needs 11mA to work. can I drive a power amplifier via  GPIO pin.?

Please replay.

[ketiljo]

Well, the spec says that  IOH in high drive is 9 mA. But this is at VDD - 0.4 V on the pin and with VDD = 2.7 V . When you increase the current draw, the voltage will drop. Also, the pin can deliver less voltage if VDD is lower. It may or may not be ok, depending on the supply voltage. 

The safest is to use a single mosfet to turn on the PA.