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Associate
July 2, 2024
Question

Usage of decoupling capacitor in STM32H503KBU6

  • July 2, 2024
  • 1 reply
  • 3349 views

Hi, 

     I am currently using STM32H503KBU6 MCU (32 pins). For my project the space in PCB board is critical. I have placed a LDO, Level translator, voltage supervisor and along with their associated passives in a 10mmx16mm PCB board. Now I still need to place three resistor, which I can't able to place because there is no space. My question is that is it necessary to use a high value decoupling capacitor (4.7uF) for VDD and VDDA? Because if I remove those two 4.7uF capacitor, I will get some space to place the three resistors. Kindly give me your thoughts about this. I have attached schematic images which is available in STM website.

bhavan_kumar_0-1719978260721.png

 

bhavan_kumar_1-1719978267514.png

 

 

Thanks,

Bhavan 

1 reply

Andrew Neil
Super User
July 2, 2024

@bhavan_kumar wrote:

I need to place three 0 ohms resistor for SWD debug interface


Why does that need zero-ohm resistors?

:thinking_face:

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
Associate
July 2, 2024

In order to do a SWD debug interface we need to connect the respective pin (PA13, PA14, NRST) to a 0 ohm resistor

Andrew Neil
Super User
July 2, 2024

But why zero-ohm resistors?

Why not just connect direct to your debug header/testpoints/whatever - especially as you're short of space?!

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.