Description

The M41T6x serial access TIMEKEEPER® is a low power serial RTC with a built-in 32.768 kHz oscillator. Eight registers 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, 32 KHz 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

■ Serial RTC with alarm functions

– 400 kHz I2C serial interface

– Memory mapped registers for seconds,

minutes, hours, day, date, month, year, and

century

– Tenths/hundredths of seconds register

■ 350 nA timekeeping current at 3 V

■ Timekeeping down to 1.0 V

■ 1.3 V to 4.4 V I2C bus operating voltage

– 4.4 V max VCC suitable for lithium-ion

battery operation

■ Low operating current of 35 µA (at 400 kHz)

■ 32 KHz square wave output is on at power-up.

Suitable for driving a microcontroller in

low-power mode. Can be disabled.

(M41T62/63/64)

■ Programmable 1 Hz to 32 KHz square wave

output (M41T62/63/64)

■ Programmable alarm with interrupt function

(M41T62/65)

■ 32 KHz crystal oscillator integrates crystal load

capacitors, works with high series resistance

crystals

■ Oscillator stop detection monitors clock

operation

■ Accurate programmable watchdog

– 62.5 ms to 31 min timeout

■ Software clock calibration. Can adjust

timekeeping to within ±2 parts per million (±5

seconds per month)

■ Automatic leap year compensation

■ –40 to +85 °C operation

■ Very small 3 mm x 3 mm, Lead-free

16-lead QFN