Datasheet

DS3232M
±5ppm, I
2
C Real-Time Clock with SRAM
8Maxim Integrated
Pin Configuration
Pin Description
PIN NAME FUNCTION
1 32KHZ
32.768KHZ Output (Push-Pull Output, 50% Duty Cycle). If enabled (EN32KHZ = 1), the 32kHz output is
active on V
CC
. If enabled for battery operation (BB32KHZ = 1), the output is also active on V
BAT
. When
disabled, the output is forced low. This pin can be left unconnected if not used.
2 V
CC
DC Power Pin for Primary Power Supply. This pin should be decoupled using a 0.1FF to 1.0FF capacitor.
Connect to ground if not used.
3
INT/
SQW
Active-Low Interrupt or 1Hz Square-Wave Output. This open-drain pin requires an external pullup resistor
connected to a supply at 4.5V or less. It can be left open if not used. This multifunction pin is determined
by the state of the INTCN bit in the Control register (0Eh). When INTCN is set to logic 0, this pin outputs
a 1Hz square wave. When INTCN is set to logic 1, a match between the timekeeping registers and either
of the alarm registers activates the INT/SQW pin (if the alarm is enabled). Because the INTCN bit is set to
logic 1 when power is first applied, the pin defaults to an interrupt output with alarms disabled.
4
RST
Active-Low Reset. This pin is an open-drain input/output. It indicates the status of V
CC
relative to the V
PF
specification. As V
CC
falls below V
PF
, the RST pin is driven low. When V
CC
exceeds V
PF
, for t
RST
, the
RST pin is pulled high by the internal pullup resistor. The active-low, open-drain output is combined with
a debounced pushbutton input function. This pin can be activated by a pushbutton reset request. It has
an internal 50kI (R
PU
) nominal value pullup resistor to V
CC
. No external pullup resistors should be con-
nected. If the oscillator is disabled, t
REC
is bypassed and RST immediately goes high.
5 GND Ground
6 V
BAT
Backup Power-Supply Input. When using the device with the V
BAT
input as the primary power source, this
pin should be decoupled using a 0.1FF to 1.0FF low-leakage capacitor. When using the device with the V
BAT
input as the backup power source, the capacitor is not required. If V
BAT
is not used, connect to ground. The
device is UL recognized to ensure against reverse charging when used with a primary lithium battery. Go to
www.maximintegrated.com/qa/info/ul for more information.
7 SDA
Serial-Data Input/Output. This pin is the data input/output for the I
2
C serial interface. This open-drain pin
requires an external pullup resistor. The pullup voltage can be up to 4.5V, regardless of the voltage on V
CC
.
8 SCL
Serial-Clock Input. This pin is the clock input for the I
2
C serial interface and is used to synchronize data
movement on the serial interface. The pullup voltage can be up to 4.5V, regardless of the voltage on V
CC
.
DS3232M
V
BAT
GNDRST
1
2
8
7
SCL
SDAV
CC
INT/SQW
32KHZ
SO
TOP VIEW
3
4
6
5
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