What should be the HSE (bypass clock source) characteristics for STM32F7 to work fine?

[HSafa]

Hello everyone,

I have an STM32F765VI MCU. When I work with internal clock it works fine. But when I switch to an external TCXO, It does not work properly. The TCXO output is a 26MHz sine wave with 1.5V peak to peak.

Does anyone know what may cause this problem?

What is the minimum amplitude of external clock which MCU can detect?

Thanks

[Tesla DeLorean]

Should be in the Data Sheet - "High-speed external user clock characteristics"

VIL is 0 to 1 V

VIH is 2.3 to 3.3 V

Expect you'd need to buffer or center the sine for it to work. Could try the non-bypass mode