STM32L4 HSI16 accuracy / stability

[PRuss]

Hi,

I am trying to get some clarification on the accuracy of the STM32L4's HSI16. AN4736 mentions that the HSI16 will leave ST's factory calibrated to [-0.75%, 0.5%] at 30 C. DS11453 section 6.3.8 shows that the drift over 0 to 85 C will be -1% to 1%. Is this in addition to the [-0.75%, 0.5%] so that the total drift over temperature could be up to -1.75%? Or is [-1%, 1%] the total drift?

Also, the HSI16 stabilization time is given as 5 us max. Can the frequency be considered as 100% of its final value after this time?

[waclawek.jan]

I'd formulate it so that the total deviation of HSI16 from nominal frequency in the given temperature range is up to -1.75%, without additional calibration.

> Also, the HSI16 stabilization time is given as 5 us max. Can the frequency be considered as 100% of its final value after this time?

Yes, that's the purpose of that parameter.

Please note that I am not ST.

JW

[Bouraoui Chemli · Accepted solution]

Hello @PRuss​ 

The total HSI16 oscillator frequency drift over temperature (0 to 85°C) is -1% to 1% as mentioned in STM32L431 datasheet DS11453.

The HSI16 oscillator stabilization time is 5 µs max, so the frequency can reach 100% of its value after this time.

Best regards

Bouraoui

[PRuss]

It's good to get clarification that this is the total drift, and the stabilization time is to 100%. Thanks!