Is that possible to inject five volt level of external clock on OSC_IN?

treguy · ‎2026-03-30

Hi,

I need to use a 5V external clock for an stm32g473. The datasheet in table 39. High-speed external user clock characteristics says Vhsel is max Vdd, but Table 12. STM32G473xB/xC/xE pin definition says PF0 / OSC_IN is FT_a (five volt tolerant).

Is it safe to use an external 5V clock ?

Thx,

mƎALLEm · ‎2026-04-14

Hello,

The design confirms that these pins are five volt tolerant only if they are used as GPIOs but the IO levels follow the levels indicated in table 39 when it is used as oscillator input i.e. they are not five volt tolerant in this case.

This applies to HSE (OSC_IN) and LSE (OSC32_IN) as well.

Hope it does answer your question.

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mƎALLEm · ‎2026-03-31

Hello,

I'm checking internally. I'll get back to you.

Internal tickets for follow-up: CDM0061203

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.

mƎALLEm · ‎2026-04-14

Hello,

The design confirms that these pins are five volt tolerant only if they are used as GPIOs but the IO levels follow the levels indicated in table 39 when it is used as oscillator input i.e. they are not five volt tolerant in this case.

This applies to HSE (OSC_IN) and LSE (OSC32_IN) as well.

Hope it does answer your question.

To give better visibility on the answered topics, please click on "Accept as Solution" on the reply which solved your issue or answered your question.