M41T00
2/15
Figure 2. SOIC Connections
1
2
3
4
SDA
VSS
SCL
FT/OUT
OSCO
VBAT
OSCI
VCC
AI00531
M41T00
8
7
6
5
Table 2. Absolute Maximum Ratings
Symbol
T
A
Ambient Operating Temperature
T
STG
Storage Temperature (V
CC
Off, Oscillator Off)
V
IO
Input or Output Voltages
V
CC
Supply Voltage
I
O
Output Current
P
D
Power Dissipation
Note: Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of
this specification is not implied. Exposure to the absolute maximum rating conditions for extended periods of time may affect reliability.
CAUTION:
Negative undershoots below –0.3V are not allowed on any pin while in the Battery Back-up mode.
Parameter
Value
Unit
–40 to 85
°C
–55 to 125
°C
–0.3 to 7
V
–0.3 to 7
V
20
mA
0.25
W
The M41T00 clock has a built-in power sense cir-
cuit which detects power failures and automatical-
ly 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 5years
with a 50mA/h 3V lithium cell. The M41T00 is sup-
plied in 8 lead Plastic Small Outline package.
OPERATION
The M41T00 clock operates as a slave device on
the serial bus. Access is obtained by implementing
a start condition followed by the correct slave ad-
dress (D0h). The 8 bytes contained in the device
can then be accessed sequentially in the following
order:
1.
Seconds Register
2.
Minutes Register
3.
Century/Hours Register
4.
Day Register
5.
Date Register
6.
Month Register
7.
Years Register
8.
Control Register
The M41T00 clock continually monitors V
CC
for an
out of tolerance condition. Should V
CC
fall below
V
SO
, the device terminates an access in progress
and resets the device address counter. Inputs to
the device will not be recognized at this time to
prevent erroneous data from being written to the
device from an out of tolerance system. When V
CC
falls below V
SO
, the device automatically switches
over to the battery and powers down into an ultra
low current mode of operation to conserve battery
life. Upon power-up, the device switches from bat-
tery to V
CC
at V
SO
and recognizes inputs.