M41T56

Description

Doc ID 6104 Rev 9

5/27

1

Description

The M41T56 is a low-power, serial real-time clock (RTC) with 56 bytes of NVRAM. A built-in

32,768 Hz oscillator (external 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, bidirectional bus. The built-in

address register is incremented automatically after each WRITE or READ data byte.

The M41T56 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 RAM and clock operations can be supplied from a small lithium coin cell.

Typical data retention time is in excess of 10 years with a 50 mAh, 3 V lithium cell. The

M41T56 is supplied in an 8-lead plastic SOIC package.

Figure 1.

Logic diagram

AI02304B

OSCI

VCC

M41T56

VSS

SCL

OSCO

SDA

FT/OUT

VBAT