ISL12032 pdf datasheet (Low Po

Low Power RTC with Battery Backed SRAM and 50/60 Cycle AC Input and Xtal Back-up
The ISL12032 device is a low power real time clock with
50/60 AC input for timing synchronization. It also has an
oscillator utilizing an external crystal for timing back-up,
clock/calendar registers, intelligent battery back-up
switching, battery voltage monitor, brownout indicator,
integrated trickle charger for super capacitor, single periodic
or polled alarms, POR supervisory function, and up to 4
Event Detect with time stamp. There are 128 bytes of
battery-backed user SRAM.
The oscillator uses a 50/60 cycle sine wave input, backed by
an external, low-cost, 32.768kHz crystal. The real time clock
tracks time with separate registers for hours, minutes, and
seconds. The calendar registers contain the date, month,
year, and day of the week. The calendar is accurate through
year 2100, with automatic leap year correction and auto
daylight savings correction.