AN2867 compatible crystal tables

[BobaJFET]

I am currently choosing an LSE and HSE crystal for an STM32H743 project. AN2867 includes tables of compatible STM32 crystals. There is also a crystal selection tool from ECS which i've used. My question is, after selecting a crystal from the tables, is there still a need to perform any of the steps outlined in section "4.2: How to select an STM32-compatible crystal"? Is it enough to simply select a crystal from the table, follow the board layout guidelines, and check the crystal frequency with an oscilloscope? 

Thank you. 

[Imen.D · Accepted solution]

Hello @BobaJFET ,

The AN2867 is a good starting point, and it is important to follow the guidelines provided in this document.

It is recommended to perform the steps outlined in section "4.2: How to select an STM32-compatible crystal" to ensure compatibility and optimal performance. This includes checking the load capacitance, oscillator transconductance, and other relevant parameters.

You should also consider the STM32H743 Datasheet which provides the supported oscillator characteristics:  frequency range and other critical parameters such as the crystal's gain margin or maximum critical crystal value needed for start-up.

Ensure that you follow the layout guidelines provided in the application note and datasheet to minimize parasitic capacitance and other layout issues.

After selecting the crystal and following the layout guidelines, it is important to verify the crystal frequency with an oscilloscope to ensure it operates correctly within the specified parameters.