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Deepu joy
Associate II
September 11, 2023
Solved

USB VBAT and controller power

  • September 11, 2023
  • 1 reply
  • 745 views

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 ? 

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Best answer by Peter BENSCH

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

1 reply

Peter BENSCH
Peter BENSCHBest answer
Technical Moderator
September 11, 2023

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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