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Associate II
December 9, 2024
Solved

Does STM32H743 have integrated crystal load capacitors?

  • December 9, 2024
  • 3 replies
  • 1873 views

I notice that on the NUCLEO-H753ZI board schematic and BOM, the load capacitors are not populated for X2. My thought is that these caps must exist elsewhere, either built into the crystal, or integrated into the STM32H743.. But I do not see any mention of integrated capacitors for either the microcontroller or the NX3215SA crystal datasheets. How can this work? 

NUCLEO-H753ZI - STM32 Nucleo-144 development board with STM32H753ZI MCU, supports Arduino, ST Zio and morpho connectivity - STMicroelectronics

BobaJFET_0-1733770911419.png

 

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Best answer by Tesla DeLorean

No, you'll need load caps. The 32 KHz used to be a DNF also, on a lot of the NUCLEO boards

h753zi_32khz.jpg

Pull the BoM from the product's "CAD Resources" tab/page

Check if X2 using a 6, 9 or 12pF crystal. Most of the ST parts used/expected 6-7pF crystals

3 replies

Tesla DeLorean
Tesla DeLoreanBest answer
Guru
December 9, 2024

No, you'll need load caps. The 32 KHz used to be a DNF also, on a lot of the NUCLEO boards

h753zi_32khz.jpg

Pull the BoM from the product's "CAD Resources" tab/page

Check if X2 using a 6, 9 or 12pF crystal. Most of the ST parts used/expected 6-7pF crystals

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BobaJFETAuthor
Associate II
December 10, 2024

Much appreciated. 

mƎALLEm
ST Technical Moderator
December 10, 2024

Hello @BobaJFET ,

I think schematics is missing C71 and C72 capacitors as X2 is soldered. So either you solder X2, C71, C71 or you can unsolder all of them if the external crystal is not used.

There is no internal CL capacitors on the chip.

 

 

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