Summary description
The M41T00SC64 is a low power, Serial Real Time Clock plus a 64Kb EEPROM (see Figure 3). A built-in 32,768Hz oscillator (crystal controlled) and the first 8 bytes of the RAM are used for the clock/calendar function and are configured in binary coded decimal (BCD) format. Addresses and data are transferred serially via a two-line, bi-directional bus. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T00SC64 clock has a built-in power sense circuit which detects power failures and automatically switches to the battery supply during power failures. The energy needed to sustain the clock operations can be supplied from a small lithium coin cell.
Typical data retention time for the Serial RTC is in excess of 9.5 years with a 50mAh, 3V lithium cell. The M41T00SC64 is supplied in an 18-lead Plastic SOIC package.

Features
■ 2.7V to 5.5V supply voltage
■ I2C bus compatible
■ Operating temperature of –40 to 85°C
■ Packaging includes:
   – 18-lead SOIC (with embedded crystal)
■ RoHS compliant

Serial RTC features (M41T00S)
■ Counters for seconds, minutes, hours, day, date, month, years, and century
■ Embedded crystal package
■ Software clock calibration
■ Factory calibrated to ± 5ppm
■ Automatic power-fail detect and switch-over circuitry
■ Ultra-low battery supply current of 600nA (typ)
■ Automatic leap year compensation
■ Special software programmable output
■ Two-wire I2C serial interface supports 400kHz protocol

Serial EEPROM features (M24C64)
■ 8192 bytes of general purpose EEPROM
   (more than 1E6 erase/write cycles)
■ Two-wire I2C serial interface supports 400kHz protocol
■ Byte and page write (up to 32 bytes)
■ More than 40 year data retention
■ Self-timed programming cycle