Datasheet

M41T00S Description
Doc ID 10772 Rev 5 5/28
1 Description
The M41T00S is a low-power serial real-time clock (RTC) with a built-in 32.768 kHz
oscillator (external crystal controlled). Eight bytes of the SRAM (see Table 2 on page 13) 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 I
2
C interface.
The built-in address register is incremented automatically after each WRITE or READ data
byte.
The M41T00S has a built-in power sense circuit which detects power failures and
automatically switches to the battery supply when a power failure occurs. The energy
needed to sustain the clock operations can be supplied by a small lithium button supply
when a power failure occurs. The eight clock address locations contain the century, year,
month, date, day, hour, minute, and second in 24-hour BCD format. Corrections for 28, 29
(leap year - valid until year 2100), 30 and 31 day months are made automatically.
The M41T00S is supplied in an 8-pin SOIC.
Figure 1. Logic diagram
Table 1. Signal names
XI Oscillator input
XO Oscillator output
FT/OUT Frequency test / output driver (open drain)
SDA Serial data input/output
SCL Serial clock input
V
BAT
Battery supply voltage
V
CC
Supply voltage
V
SS
Ground
SCL
V
CC
M41T00S
V
SS
SDA
FT/OUT
V
BAT
XI
XO
AI09165