This RTC IC has been specially designed to achieve an ultra-low power consumption of typically 130nA @ VDD 3.0V in time-keeping mode. The very small SMT ceramic-package combines the 32.768 kHz crystal unit with the CMOS-based oscillator and real-time-clock circuitry. The calendar function tracks year, month, date, and day-of-the-week with built-in century and leap-year fl ags. The clock function tracks minute and second in 24-hour format. Programmable alarm setting, dual timer functions and integrated switch-over circuitry to backup supply voltage increase fl exibility.