replacemnt for X53T-C20SSA-25.000MHz used by LAN8742Ai in STM32H7xxI-Eval

[MFawzy]

Hi,

I’m working on designing a custom board for industrial applications and would like to use the crystal X53T-C20SSA-25.000MHz, which is used in the STM32H7xxI-EVAL board for the LAN8742Ai PHY. However, I can’t find this crystal available anywhere. My questions are:

1. What is the best replacement for industrial use?

2. What capacitor values should be used if the crystal is changed?

Additionally, is the ABM8W-25.0000MHZ-8-D1X-T3 a suitable replacement? If so, what capacitor values should be used?

Thanks,

Mohammed

[MHoll.2 · Accepted solution]

The STM32H7xxI-EVAL board is quit old, so some componets are no longer in production. For the LAN8742Ai Crystal You should refer to the Datasheet from Microchip (DS00001989A) chapter 5.7. The Datasheet clames that You can user 300uW or 100uW crystals, when using 100uW You need to add a seriale resistor. The proposed ABM8W-25.0000MHZ-8-D1X-T3 is a 100uW type so needs the resistor.

[Tesla DeLorean]

The original Microchip reference used

HC49US-FF5F18-25.000MHZ

25 MHz ±30ppm Crystal 18pF 30 Ohms HC-49/U

If you're looking to copy a design/parts NX2016SA 25MHz w/5.6pF load caps, see NUCLEO-H723ZG reference design.

NX2016SA 25MHz EXS00A-CS11321

Crystal 25MHz, 6pF, +-20ppm, 80ohms max, SMD

https://community.st.com/t5/stm32-mcus-products/lan8742a-stm32-and-ref-clk/td-p/618654

[momonidexiong]

X53T-C20SSA-25.000MHz, I bought it from my supplier, do you need a recommendation?

[Andrew Neil]

This is really nothing to do with the STM32 or ST: it's purely a matter of the LAN8742Ai  - so you really should be asking Microchip for support with their product:

https://www.microchip.com/en-us/product/lan8742a

https://www.microchip.com/en-us/support