Electronic – the use of the capacitors in this schematic

capacitorstm32

I'm using an STM32L476RG microcontroller where the recommended schematic is as follows –

Enter image description here

I was wondering what the purpose of C25 and C22 were, as SB38 and SB32 are shorted on my Nucleo development board. So, what is the purpose of these capacitors when they are shorted?

Since the picture is unclear, I have attached the link to the reference manual here. The schematic is on page 64 of the STM32L476RG reference manual.

Why have they used C25 and C22 when SB38 and SB33 are shorted in the schematic?

Best Answer

Based on experience with other devices from the STM32 family I can tell the Vcap is a capacitor used to the internal voltage regulator. This is a mandatory part.

However, the STM32L476RG does not have Vcap pins. But the STM32 families are closely pin compatible. With only a few modifications.

I suspect your example board is suitable for more than only the STM32L476RG, and can also be used for part that do need Vcap. On you're part it's just Vdd/Vss, as for why the jumpers are shorted.

There is also a note on the schematic, mentioning VCAP for the F200 and F429:

enter image description here

F200/F429:VCAP1
F373:SD_VREF+
F373:PB14
F373:PB15
F373:PD8
F030R8/F373:PF6 & F200/F429:VCAP2
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