The ISL12027 device is a low power real time clock with timing and crystal compensation, clock/calender, power-fail indicator, two periodic or polled alarms, intelligent battery backup switching, CPU Supervisor and integrated 512x8-bit EEPROM, in 16 Byte per page format.
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 ISL12027 and ISL12027A Power Control Settings are different. The ISL12027 uses the Legacy Mode Setting, and the ISL12027A uses the Standard Mode Setting. Applications that have VBAT > VDD will require only the ISL12027A. Please refer to“Power Control Operation” on page 15 for more details. Also, please refer to “I2C Communications During Battery Backup and LVR Operation” on page 24 for important details.

Features
• Real Time Clock/Calendar
   - Tracks Time in Hours, Minutes and Seconds
   - Day of the Week, Day, Month and Year
• Two Non-Volatile Alarms
   - Settable on the Second, Minute, Hour, Day of the Week,
      Day, or Month
   - Repeat Mode (Periodic Interrupts)
• Automatic Backup to Battery or SuperCap
• On-Chip Oscillator Compensation
   - Internal Feedback Resistor and Compensation
      Capacitors
   - 64 Position Digitally Controlled Trim Capacitor
   - 6 Digital Frequency Adjustment Settings to ±30ppm
• 512x8-Bits of EEPROM
   - 16-Byte Page Write Mode (32 total pages)
   - 8 Modes of BlockLock™ Protection
   - Single Byte Write Capability
• High Reliability
   - Data Retention: 50 years
   - Endurance: >2,000,000 Cycles Per Byte
• I2C-bus™ Interface
   - 400kHz Data Transfer Rate
• 800nA Battery Supply Current
• Package Options
   - 8 Ld SOIC and 8 Ld TSSOP Packages
• Pb-Free (RoHS Compliant)

Applications
• Utility Meters
• HVAC Equipment
• Audio/Video Components
• Modems
• Network Routers, Hubs, Switches, Bridges
• Cellular Infrastructure Equipment
• Fixed Broadband Wireless Equipment
• Pagers/PDA
• POS Equipment
• Test Meters/Fixtures
• Office Automation (Copiers, Fax)
• Home Appliances
• Computer Products
• Other Industrial/Medical/Automotive