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Description

The M41T6x is a low-power serial real-time clock (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. Further eight

registers provide status/control of alarm, 32 kHz output, calibration, and watchdog functions. Addresses and data

are transferred serially via a two-line, bidirectional I²C interface. The built-in address register is incremented

automatically after each WRITE or READ data byte.

Functions available to the user include a time-of-day clock/calendar, an alarm interrupt (M41T62/M41T65), a 32

kHz output (M41T62/M41T64), a programmable square wave output (M41T62/M41T64), and a watchdog output

(M41T65). The eight clock address locations contain the century, year, month, date, day, hour, minute, second

and tenths/hundredths of a second in 24-hour BCD format. Corrections for 28-, 29- (leap year), 30- and 31-day

months are made automatically.

The M41T6x is supplied in two very small packages: a tiny, 3 x 3 mm 16-pin QFN which requires a user-supplied

32 kHz crystal, and an ultra-small 1.5 x 3.2 mm LCC with embedded crystal - no external crystal is required.

Device

Basic RTC

Alarms

OSC fail

detect

Watchdog timer

Calibration

SQW

output

IRQ output

WDO output

output

M41T62

✓

✓

✓

✓

✓

✓

✓

M41T64

✓

✓

✓

✓

✓

✓

✓

M41T65

✓

✓

✓

✓

✓

✓

✓

SCL

M41T62

SDA

XI

(3)

XO

(3)

1.

Open drain.

2.

Defaults to 32 kHz on power-up.

3.

Not bonded on LCC package.

M41T62, M41T64, M41T65

Description

DS3840 - Rev 24

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