Hello, I am using STM32L4R9AI, the MCU VDD is powered at 1.8v and VDDA at 3.3v. in the recommended design by ST, there is ferite bead between MCU VDD and VDDA, ferite bead is basically inductor which acts as short circuit for DC current, so how can I short between 3.3v and 1.8v? or is there other way to connect it?
Thanks in Advance!
Not a hardware guy.
> ... there is ferite bead between MCU VDD and VDDA, ferite bead is basically inductor which acts as short circuit for DC current, ...
No, it is usually intended as lowpass filter, to suppress ripples generated by fluctuations in the power consumptions.
> ...so how can I short between 3.3v and 1.8v? or is there other way to connect it?
You don't need to follow this suggestion of the reference design. Connecting VDD and VDDA is the cheap variant, sacrificing analog stability/accuracy for BOM costs.
But the separate VDD/VDDA pins allow you to keep the supplies separate, if it is advantageous for your design.
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