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RF switch supply from GPIO pin as output?

AZube.2
Associate III

Can anyone confirm if it is okay to supply the RF switch directly from a general purpose output of the STM32WL? This way I could control when the switch is working or when the antenna is isolated (off) from the circuit.

I see in the datasheet for the STM32WL that "The GPIOs can sink or source up to ±8 mA, and sink or source up to ± 20 mA (with a relaxed VOL/VOH)". While for the RF switch the typical supply current is of 65uA and a maximum of 110uA.

Seems that it should be okay. Could anyone that has done this or anyone with the knowledge confirm this is a good practice?

Thanks and best regards,

Asier

1 ACCEPTED SOLUTION

Accepted Solutions
Benoit MARCHAND
Associate III

Hello,

Yes, it is perfrectly fine to control RFSwitch through GPIOs.

This is what is done on stm32wl nucleo board (https://www.st.com/en/evaluation-tools/nucleo-wl55jc.html)

You can find an implementation of the control in stm32cubewl (https://www.st.com/en/embedded-software/stm32cubewl.html) in the ATSlave application example.

BR,

Benoit

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2 REPLIES 2
Andrew Neil
Evangelist

Well, ST's own B-L072Z-LRWAN1 board supplies its TCXO from a port pin - so it should be fine to supply just an RF switch...

Benoit MARCHAND
Associate III

Hello,

Yes, it is perfrectly fine to control RFSwitch through GPIOs.

This is what is done on stm32wl nucleo board (https://www.st.com/en/evaluation-tools/nucleo-wl55jc.html)

You can find an implementation of the control in stm32cubewl (https://www.st.com/en/embedded-software/stm32cubewl.html) in the ATSlave application example.

BR,

Benoit