Low Power RTC with Battery Backed SRAM, Integrated ±5ppm TemperatureCompensation, and Auto Daylight SavingThe ISL12022M device is a low power real time clock (RTC)with an embedded temperature sensor and crystal. Devicefunctions include oscillator compensation, clock/calendar,power fail and low battery monitors, brownout indicator,one-time, periodic or polled alarms, intelligent batterybackup switching, Battery Reseal™ function and 128 bytesof battery-backed user SRAM. The device is offered in a20 Ld SOIC module that contains the RTC and anembedded 32.768kHz quartz crystal. The calibratedoscillator 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 through2099, with automatic leap year correction.Daylight Savings time adjustment is done automatically,using parameters entered by the user. Power fail and batterymonitors offer user-selectable trip levels. The time stampfunction records the time and date of switchover from VDD toVBAT power, and also from VBAT to VDD power.