Description

M41T00CAP

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Doc ID 14557 Rev 5

1

Description

The M41T00CAP is a low-power serial real-time clock (RTC) with integral battery and

crystal in ST’s 24-pin CAPHAT™ package. It includes a crystal controlled, 32.768 kHz

oscillator and has a built-in power sense circuit which detects power failures and

automatically switches to the backup battery when a power failure occurs.

Eight registers comprise the clock/calendar function and are configured in binary-coded

decimal (BCD) format. Addresses and data are transferred serially via an industry standard,

automatically after each WRITE or READ data byte. The internal lithium coin cell contains

ample energy to sustain timekeeping operation for 10 years in the absence of system power.

The eight clock address locations contain the century, year, month, date, day, hour, minute,

and second in 24-hour BCD format. Corrections for the number of days in a month, including

leap year, are made automatically (leap year valid up to year 2100).

Figure 1.

Logic diagram

SCL

VCC

M41T00CAP

VSS

SDA

FT/OUT

AI09165