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 backup battery current draw is less than 1.6µA over the temperature range. 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 the switchover from VDD to VBAT power, and also from VBAT to VDD power.