SUMMARY DESCRIPTION
The M41T6x Serial Access TIMEKEEPER® is a low power Serial RTC with a built-in 32.768 kHz oscillator (external crystal controlled). Eight registers (see Table 3., page 14) are used for the clock/ calendar function and are configured in binary coded decimal (BCD) format. An additional 8 registers provide status/control of Alarm, 32KHz output, Calibration, and Watchdog functions. Addresses and data are transferred serially via a two line, bi-directional I2C interface. The built-in address register is incremented automatically after each WRITE or READ data byte.

FEATURES SUMMARY
■ 350nA TIMEKEEPING CURRENT @ 3V
■ TIMEKEEPING DOWN TO 1.0V
■ 1.3V TO 3.6V I2C BUS OPERATING
   VOLTAGE
■ COUNTERS FOR TENTHS/HUNDREDTHS
   OF SECONDS, SECONDS, MINUTES,
   HOURS, DAY, DATE, MONTH, YEAR, AND
   CENTURY
■ SERIAL INTERFACE SUPPORTS I2C BUS
   (400kHz)
■ PROGRAMMABLE ALARM WITH FLAG BIT
   ONLY (M41T63/64)
■ PROGRAMMABLE ALARM WITH FLAG BIT
   AND INTERRUPT FUNCTION (M41T62/65)
■ LOW OPERATING CURRENT OF 35µA
■ SOFTWARE CLOCK CALIBRATION
■ OSCILLATOR STOP DETECTION
■ 32KHz SQUARE WAVE ON POWER-UP
   (M41T62/63/64)
■ WATCHDOG TIMER
■ WATCHDOG OUTPUT (M41T63/65)
■ AUTOMATIC LEAP YEAR COMPENSATION
■ OPERATING TEMPERATURE OF –40 TO
   85°C
■ LEAD-FREE 16-PIN QFN PACKAGE
■ TOTAL SURFACE AREA OF IC AND 32KHz
   CRYSTAL IS 21.5mm2