2025-02-10 08:22 AM
Hello
Which are the correct Capacitors to use for HSE on STM32F103 with the following Crystal?
Frequency: 8 MHz
Load capacitance CL: 20 pF
Thank you in advance for a quick hint.
Regards
Michael
2025-02-10 08:28 AM
Welcome @Michael_CH, to the community!
You have provided too little information for a qualified answer. Essentially, however, you will find everything in detail in AN2867.
Hope that helps?
Regards
/Peter
2025-02-10 08:53 AM
I am not an engineer, but just a hobbyist trying to make my first schematic and a PCB.
I was looking the AN, but honestly that was too complex for me.
Therefore i hope some more experienced people can tell me the correct value for the 2 capacitors there.
Which information is missing?
Thank you.
2025-02-10 09:02 AM
Firstly, the data sheet of the crystal used is important, from which you can see the key values: C0, CL and ESR.
Furthermore, the AN2867 mentioned above also contains important notes on layout from section 7 onwards, which you should read and try to understand.
2025-02-10 10:00 AM
So just look at the "blue pill" circuit, as an example:
or at circuit of STM nucleo boards:
So choosing 2x 20 pF should be ok; (out of the typical range 12...20 pF)
2025-02-10 10:03 AM
Crystal datasheet:
https://datasheet.lcsc.com/szlcsc/1903061615_Yangxing-Tech-X50328MSB2GI_C115962.pdf
CL i already provided: 20 pF
C0: 3 pF max.
ESR: 80Ω max.
Hope that help you to help me. :)
2025-02-10 10:03 AM
@Michael_CH wrote:I am not an engineer, but just a hobbyist trying to make my first schematic and a PCB.
But designing an electronic is an engineering exercise!