DESCRIPTION
The X1243 is a Real Time Clock with clock/calendar circuits and two alarms. The dual port clock and alarm registers allow the clock to operate, without loss of accuracy, even during read and write operations. 

FEATURES
• 2 Alarms—Interrupt Output
   —Settable on the Second, 10s of Seconds, Minute, 10s of Minutes, Hour, Day, Month, or Day of the Week
   —Repeat alarm for time base generation
• 2 Wire Interface interoperable with I2C.
   —400kHz data transfer rate
• Secondary Power Supply Input with internal switch-over circuitry.
• Year 2000 Compliant
• 2K bytes of EEPROM
   —64 Byte Page Write Mode
   —3 bit Block Lock
• Low Power CMOS
   —<1µA Operating Current
   —<3mA Active Current during Program
   —<400µA Active Current during Data Read
• Single Byte Write Capability
• Typical Nonvolatile Write Cycle Time: 5ms
• High Reliability
   —100,000 Endurance Cycles
   —Guaranteed Data Retention: 100 Years
• Small Package Options
   —8-Lead SOIC Package, 8L TSSOP Package