The ISL12026 and the ISL12026A devices are micro power real time clocks with timing and crystal compensation， clock/calender， power-fail indicator， two periodic or polled alarms， intelligent battery backup switching， and integrated 512x8-bit EEPROM configured in 16 Bytes per page. The oscillator uses an external， low-cost 32.768kHz crystal. The real time clock tracks time with separate registers for hours， minutes， and seconds. The device has calendar registers for date， month， year and day of the week. The calendar is accurate through 2099， with automatic leap year correction. The ISL12026 and ISL12026A have different types of Power Control Settings. The ISL12026 uses the Legacy Mode Setting， which follows conditions set in X1226 products. The ISL12026A uses the Standard Mode Setting. Please refer to “Power Control Operation” on page 13 for more details. Also， please refer to “I2C Communications During Battery Backup” on page 22 for important details.