RTC M41T94 reset in the temperature cycle test

[lohithbandi]

Hi 

We are using the M41T94 RTC IC in our board. In the temperature test, we are observing the RTC reset. 

Reset to the initial date and time. 

This is causing the log and data mismatch.

Test Details:

• Temperature cycling: 2 cold and 2 hot cycles
• Range: -40 °C to +62 °C
• Dwell time: 45 minutes per cycle
• Ramp rate: 3 °C per minute

Issue Observed:
At temperatures between 50 °C and 60 °C, the battery voltage drops from 3 V to below 2.5 V suddenly, and it will come back to its original voltage in a quick interval. 

Battery part number: CR1225

Crystall part number: TFE322P32K7680R

@B.Montanari @RobertC @mrtc 

Please provide me the root cause with a solution to fix the issue. 

[lohithbandi]

@ron239955_stm1  @KDJEM.1 @Shreayas_Acharaya

Can you please look at the issue, give us the solution from your perspective, and it would be much appreciated.