Hi, Support Team
If we couldn’t meet the customer’s criteria for RTC accuracy, what could we do?
We have changed the capacitor’s value of 32.768KHz crystal according to crystal vendor’s suggestion.
But, the result is still fail.
schematic: I2C signal: pull-up 1k ohm to 3V Vcc
Crystal spec: 32.768KHz 12.5pF +/-20ppm
It is work on crystal X1 position according to inspection matching result as shown performance.
For X1 position, it satisfies the recommend negative resistance and frequency gap within +/-10ppm as a positive number if using parameter C1097/C1098=10/10pF move to 6.8/6.8pF according to on hand PCB testing result.
if any suggestion, Please advise me,
Thanks,
Best regards,
Lawrence
