2021-08-05 09:40 AM
Hi,
I am looking for an STM based MCU/kit with high accuracy crystal oscillator with possible option to fine tune the frequency. I want to use it for some high accuracy time reference. Looking for suggestion please.
- ijaz
2021-08-05 10:24 AM
Crystals are high accuracy by their very nature. As long as it uses one, it should be accurate to tens of ppm. What accuracy do you need?
The STM32H7 series can use fractional PLL loop to further tune the clock.
This uses a crystal (NX3225GD-8MHz-EXS00A-CG04874) accurate to ±20 ppm. Probably can't get much better with ST boards.
https://www.st.com/en/evaluation-tools/nucleo-h743zi.html
2021-08-05 10:25 AM
Define "hifg accuracy" and "fine tune range"
2021-08-05 10:42 AM
Can't you just mount a VCTCXO ? How hard can that be? Wire it to a DAC with a LPF.
SiTime has a part you can trim via I2C
How about using a LEA-M8F, clocking the STM32 with the 30.72 MHz? GNSS locked that's good to 5ppb
The Murata module here claims to have a TCXO +/- 2ppm, near term probably a fraction of that.
https://www.st.com/en/evaluation-tools/b-l072z-lrwan1.html
2021-08-05 10:48 AM
Cause some of us have higher standards than others..
2021-08-05 11:29 AM
Actually I need a board with stable oscillator from 0-degree to 50-degree temperature. I want to measure accurate signal time over 12hrz. I heard that normal crystal oscillators have some variations over temperature. A board I know is STM32WB which i guess provide crystal tuning.
2021-08-05 11:30 AM
I want to measure accurate signal time over 12hrz. I heard that normal crystal oscillators have some variations over temperature.
2021-08-05 11:31 AM
2021-08-05 11:34 AM
Actually I want to measure a signal time over 12hrz long via STm32 timer. for that purpose I need a reference board with stable XTL frequency.
2021-08-05 11:37 AM
I am not very familiar with XTL accuracies but (in term of time) I want the Timer being fed from it to have max 3msec variation in 24Hrz. I am feeding the on-chip timer from XTL.