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Possible to keep VDD33USB as NC if USB feature not using In STM32H753ZIT6

abhilash72
Visitor

Can we  keep VDD33USB keep NC if USB feature not using In STM32H753ZIT6?

If kept NC what may go wrong? 

3 REPLIES 3
AScha.3
Super User

NC is usually not the best idea , with any digital input pin;

see ds :

AScha3_0-1747636316782.png

So you could leave it to gnd. But why not set it to vdd ? So later, if you want USB, its there.

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thanks @AScha.3 , I agree on this, I fact i suggested to keep zero ohm and tie it with VDD( 3.3V). but issue is we are in final stage of Gerber generation ( keept this pin NC) . Now need strong reason to modify it now. 

also will you check on below snap?

abhilash72_0-1747637224639.png

if not used 0v to 3.6V. I not sure if 0V to 3.6V means not we can keep it NC.

adding link of application note 

*Getting started with STM32H723/733, STM32H725/735 and STM32H730 Value Line hardware development -

FAQ: Configuring the VDD50USB and VDD33USB pins on... - STMicroelectronics Community

From ds , 0...3v6 allowed, NC should be no problem for function of cpu.

But as always: a floating input (here power input) is not the "perfect" design idea.

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