PCF8563 RTC time corrupted after 3 months of use

[Savita_Dhiman]

Hi Team,

we have used PCF8563 in one of our products. These products are out to customer site and 3 different customers from different sites have reported that RTC got corrupted one morning when they turned the unit on.

Is there any known issue (similar to this one) is associated with NXP PCF8563 ? If not what could be the possible reasons for the RTC corruption.

Thanks and Regards

Savita 

[diazmarin09]

Hello Savita,

I hope all is great with you. Thank you for using the NXP communities.

Time keeping can only be as accurate as its reference. Several environmental factors like humidity, vibration and pressure can influence RTC-accuracy but it is mainly the inferior characteristics of a quartz crystal over temperature which result in deviations if temperature is changing.

Could you please provide a detailed description of the issue?

Regards,

David

[Savita_Dhiman]

Hi David,

Thanks for the reply. Yes the overall system includes heaters, 2 pumps, water circuits. The system is meant to output the heated water out (temperature unto 45 degree Celsius, with input water temperature of about 19 degree Celsius).

Our end customers have reported that they used the system one day, left home after the shift. And the next morning when they came back, they found RTC time was corrupted specially the "Year" which they found 102.

Do you know any possible reasons for that, if you have heard anything similar in past?

Thanks and Regards

Savita Dhiman

[diazmarin09]

Hello Savita,

Unfortunately I have not heard about this issue before.

As mentioned above, the humidity might influence the accuracy of the device.

I would like to recommend the following application note. This application note describes how the use of an external temperature sensor, placed in a location which will be at or near the same temperature as the PCF8563 RTC and its crystal can improve accuracy considerably.

AN10652

In the meantime, could you please share your schematic?

If you do not want to go public, you can submit a new case.

Regards,

David