@tkuo The RTC M41T62LC6F has been set to NRND (not recommended for new designs) and will soon be obsoleted. However, the characters in the second line, 231C4 in your case, can be interpreted as follows:
- 2 = last digit of the year of manufacture (as the RTC was launched in 2003, your "2" can therefore stand for 2012 or 2022)
- 31 = calendar week of the year of manufacture
- C4 = lot number (internal)
Hope that helps?
Regards
/Peter