DS1339U-33+is used on industrial computer motherboards, After power on testing, it was found that its RTC time was getting slower and slower

The data sheet says that the CR2032 battery should be directly connected to pin 3, without the resistor and diode you show. Remove R6290 and R838 and D1. Change R132 to zero ohms and put a shorting wire between pads 1 and 3 of D1 footprint. Also, the load caps for the crystal are integrated into the DS1339, so C63 and C64 should be removed as well.

Per page 8 of the data sheet, under the description for Vbackup, "Diodes should not be placed in series between the backup source and the VBACKUP input, or improper operation will result."

The data sheet says that the CR2032 battery should be directly connected to pin 3, without the resistor and diode you show. Remove R6290 and R838 and D1. Change R132 to zero ohms and put a shorting wire between pads 1 and 3 of D1 footprint. Also, the load caps for the crystal are integrated into the DS1339, so C63 and C64 should be removed as well.

Per page 8 of the data sheet, under the description for Vbackup, "Diodes should not be placed in series between the backup source and the VBACKUP input, or improper operation will result."