ISL12022/ISL12022M pdf datashe

Low Power RTC with Battery Backed SRAM, Integrated ±5ppm Temperature
Compensation, and Auto Daylight Saving
The ISL12022M device is a low power real time clock (RTC)
with an embedded temperature sensor and crystal. Device
functions include oscillator compensation, clock/calendar,
power fail and low battery monitors, brownout indicator,
one-time, periodic or polled alarms, intelligent battery
backup switching, Battery Reseal™ function and 128 bytes
of battery-backed user SRAM. The device is offered in a
20 Ld SOIC module that contains the RTC and an
embedded 32.768kHz quartz crystal. The calibrated
oscillator provides less than ±5ppm drift over the full -40°C to
+85°C temperature range.
The RTC tracks time with separate registers for hours,
minutes, and seconds. The calendar registers track date,
month, year and day of the week and are accurate through
2099, with automatic leap year correction.
Daylight Savings time adjustment is done automatically,
using parameters entered by the user. Power fail and battery
monitors offer user-selectable trip levels. The time stamp
function records the time and date of switchover from VDD to
VBAT power, and also from VBAT to VDD power.