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2032140_en-US

2032140_en-US

PCF85363 always runs 3s ahead

Hello community,
I have bought a PCF85363 and am in the process of testing it.
Unfortunately it is running 3 seconds ahead per day.

I have tried different settings to adjust the clock. Unfortunately no success. I have also attached capacitors (33pf and 47pF) to the quartz. No success either.
At the beginning the clock ran behind, but now it always runs ahead.

What am I doing wrong?


Yours sincerely

Patrick Dreger

Re: PCF85363 always runs 3s ahead

Standard clock quartz, 32.768kHz with 12.5 load capacity.

Re: PCF85363 always runs 3s ahead

Hello Thomas,
I know that you can do offset calibration. I just wanted to avoid it.

It could have been to trick with additional capacitors.

And one more thing. This is the best 1Hz clock I have measured with oscillator. No 0.9Hz. Stable 1Hz.

Re: PCF85363 always runs 3s ahead

Hello,
I use clock quartz with 12.5pF.
I have tried all the configurations. I have even changed the quartz.

Re: PCF85363 always runs 3s ahead

Hello Patrick,

What crystal are you using? Is it a 6pF, 7pF or 12,5pF load capacitance crystal? Did you set the load capacitance bits accordingly?

Screenshot 2025-01-22 110444.png

It is possible to perform offset calibration as described in the datasheet, section 7.8.3.

You can also find some useful info in the UM10301, sections 9  and 10.

BRs, Tomas

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Last update:
‎11-21-2025 08:50 PM
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