USB VBAT and controller power

Deepu joy · ‎2023-09-11

Hi ,

I am using STM32L072CBT6 for my project. We have to use USB for configuration purpose. The controller VDD is connected to 1.8V power supply, but the VDD_USB is 3.3V. Is there any issue to connect 2 different powers ?

Peter BENSCH · ‎2023-09-11

You will have no problem with VDD=1.8V and VDD_USB=3.3V. In the data sheet, table 23, it says in footnote 3:

[...] VDD_USB is independent from VDD and VDDA: its value does not need to respect this rule. (i.e. max 300mV between any VDDx and VDDA pins do not apply for VDD_USB)

Hope that answers your question?

Good luck!
/Peter

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Peter BENSCH · ‎2023-09-11

You will have no problem with VDD=1.8V and VDD_USB=3.3V. In the data sheet, table 23, it says in footnote 3:

[...] VDD_USB is independent from VDD and VDDA: its value does not need to respect this rule. (i.e. max 300mV between any VDDx and VDDA pins do not apply for VDD_USB)

Hope that answers your question?

Good luck!
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.