real-time clock (RTC) with 236 bytes of battery-backed
SRAM. The device incorporates a battery input and
maintains accurate timekeeping when main power to the
device is interrupted. The integration of the microelec-
tromechanical systems (MEMS) resonator enhances the
long-term accuracy of the device and reduces the piece-
part count in a manufacturing line.
The RTC maintains seconds, minutes, hours, day, date,
month, and year information. The date at the end of the
month is automatically adjusted for months with fewer
than 31 days, including corrections for leap year. The
clock operates in either the 24-hour or 12-hour format
with an
AM/PM
indicator. Two programmable time-of-day
alarms and a 1Hz output are provided. Address and data
are transferred serially through an I
2
C bidirectional bus.
A precision temperature-compensated voltage reference
and comparator circuit monitors the status of V
CC
to
detect power failures, to provide a reset output, and to
automatically switch to the backup supply when neces-
sary. Additionally, the
RST
pin is monitored as a pushbut-
ton input for generating a microprocessor reset. See the
Block Diagram
for more details.
Features
S
Timekeeping Accuracy ±5ppm (±0.432 Second/
Day) from -40NC to +85NC
S
236 Bytes of Battery-Backed User SRAM
S
Battery Backup for Continuous Timekeeping
S
Low Power Consumption
S
Functionally Compatible to DS3232
S
Complete Clock Calendar Functionality Including
Seconds, Minutes, Hours, Day, Date, Month, and
Year with Leap Year Compensation Up to Year
2100
S
Two Time-of-Day Alarms
S
1Hz and 32.768kHz Outputs
S
Reset Output and Pushbutton Input with
Debounce
S
Fast (400kHz) I
2
C-Compatible Serial Bus
S
+2.3V to +4.5V Supply Voltage
S
Digital Temp Sensor with ±3NC Accuracy
S
-40NC to +85NC Temperature Range
S
8-Pin SO (150 mils) Package
S
Underwriters Laboratories (UL) Recognized
Applications
Power Meters
Industrial Applications
Typical Operating Circuit
V
CC
V
CC
Ordering Information
appears at end of data sheet.
SCL
SDA
I/O PORT
DS3232M
INT/SQW
INTERRUPTS
CPU
32KHZ
PUSH-
BUTTON
RESET
RST
V
BAT
For related parts and recommended products to use with this part, refer to:
www.maxim-ic.com/DS3232M.related
Note:
Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may
be simultaneously available through various sales channels. For information about device errata, go to:
www.maxim-ic.com/errata.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
DS3232M
±5ppm, I
2
C Real-Time Clock with SRAM
ABSOLUTE MAXIMUM RATINGS
Voltage Range on Any Pin Relative to GND ........-0.3V to +6.0V
Operating Temperature Range .......................... -40NC to +85NC
Storage Temperature Range............................ -55NC to +125NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-
tion of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED OPERATING CONDITIONS
(T
A
= -40NC to +85NC, unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage
Logic 1
Logic 0
SYMBOL
V
CC
V
BAT
V
IH
V
IL
CONDITIONS
MIN
2.3
2.3
0.7 x
V
CC
-0.3
TYP
3.3
3.0
MAX
4.5
4.5
V
CC
+
0.3
0.3 x
V
CC
UNITS
V
V
V
ELECTRICAL CHARACTERISTICS—FREQUENCY AND TIMEKEEPING
(V
CC
or V
BAT
= +3.3V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
CC
= +3.3V, V
BAT
= +3.0V, and
T
A
= +25NC, unless otherwise noted.) (Note 1)
PARAMETER
1Hz Frequency Tolerance
1Hz Frequency Stability vs. V
CC
Voltage
Timekeeping Accuracy
32kHz Frequency Tolerance
SYMBOL
Df/f
OUT
Df/V
tK
A
Df/f
OUT
CONDITIONS
Measured over
R
10s interval
Q1
Q0.432
Q2.5
MIN
TYP
MAX
Q5
UNITS
ppm
ppm/V
Seconds/
Day
%
DC ELECTRICAL CHARACTERISTICS—GENERAL
(V
CC
= +2.3V to +4.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
CC
= +3.3V, V
BAT
= +3.0V, and
T
A
= +25NC, unless otherwise noted.) (Note 1)
PARAMETER
Active Supply Current
(I
2
C Active)
Standby Supply Current
(I
2
C Inactive)
SYMBOL
I
CCA
I
CCS
(Note 2)
CONDITIONS
MIN
TYP
125
MAX
250
UNITS
µA
(Notes 2, 3)
100
175
µA
2
DS3232M
±5ppm, I
2
C Real-Time Clock with SRAM
DC ELECTRICAL CHARACTERISTICS—GENERAL (continued)
(V
CC
= +2.3V to +4.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
CC
= +3.3V, V
BAT
= +3.0V, and
T
A
= +25NC, unless otherwise noted.) (Note 1)
PARAMETER
Temperature Conversion Current
(I
2
C Inactive)
Power-Fail Voltage
Logic 0 Output
(32KHZ,
INT/SQW,
SDA)
Logic 0 Output (RST)
Logic 1 Output (32KHZ)
Output Leakage
(32KHZ,
INT/SQW,
SDA)
Input Leakage (SCL)
RST
I/O Leakage
V
BAT
Leakage
Temperature Accuracy
Temperature Conversion Time
Pushbutton Debounce
Reset Active Time
Oscillator Stop Flag (OSF) Delay
SYMBOL
I
CCSCONV
V
PF
V
OL
V
OL
V
OH
I
OL
= 3mA
I
OL
= 1mA
Active supply > 3.3V, I
OH
= -1mA
Active supply > 2.7V, I
OH
= -0.75mA
Active supply > 2.3V, I
OH
= -0.14mA
I
LO
I
LI
I
OL
I
BATLKG
TEMP
ACC
t
CONV
PB
DB
t
RST
t
OSF
(Note 4)
T
A
= +25NC
V
CC
or V
BAT
= +3.3V
2.0
2.0
2.0
-0.1
-0.1
-200
-100
25
Q3
10
250
250
25
100
+0.1
+0.1
+10
+100
µA
µA
µA
nA
NC
ms
ms
ms
ms
V
2.45
CONDITIONS
MIN
TYP
200
2.575
MAX
350
2.70
0.4
0.4
UNITS
µA
V
V
V
DC ELECTRICAL CHARACTERISTICS—V
BAT
CURRENT CONSUMPTION
PARAMETER
Active Battery Current
(I
2
C Active)
Timekeeping Battery Current
(I
2
C Inactive)
Temperature Conversion Current
(I
2
C Inactive)
Data Retention Current
(Oscillator Stopped and I
2
C
Inactive)
SYMBOL
I
BATA
I
BATT
I
BATTC
(Note 2)
EN32KHZ = 0, INTCN = 1 (Note 2)
CONDITIONS
MIN
(V
CC
= 0V, V
BAT
= +2.3V to +4.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
CC
= 0V, V
BAT
= +3.0V, and
T
A
= +25NC, unless otherwise noted.) (Note 1)
TYP
25
1.8
200
MAX
75
3.0
350
UNITS
µA
µA
µA
I
BATDR
T
A
= +25NC
100
nA
3
DS3232M
±5ppm, I
2
C Real-Time Clock with SRAM
AC ELECTRICAL CHARACTERISTICS—POWER SWITCH
(T
A
= -40NC to +85NC, unless otherwise noted.) (Note 1,
Figure 2)
PARAMETER
V
CC
Fall Time, V
PFMAX
to
V
PFMIN
V
CC
Rise Time, V
PFMIN
to
V
PFMAX
Recovery at Power-Up
SYMBOL
t
VCCF
t
VCCR
t
REC
(Note 5)
CONDITIONS
MIN
300
0
250
300
TYP
MAX
UNITS
Fs
Fs
ms
AC ELECTRICAL CHARACTERISTICS—I
2
C INTERFACE
(V
CC
or V
BAT
= +2.3V to +4.5V, T
A
= -40NC to +85NC, unless otherwise noted. Typical values are at V
CC
= +3.3V, V
BAT
= +3.0V, and
T
A
= +25NC, unless otherwise noted.) (Notes 1, 6,
Figure 1)
PARAMETER
SCL Clock Frequency
Bus Free Time Between STOP
and START Conditions
Hold Time (Repeated) START
Condition
Low Period of SCL
High Period of SCL
Data Hold Time
Data Set-Up Time
START Set-Up Time
SDA and SCL Rise Time
SDA and SCL Fall Time
STOP Set-Up Time
SDA, SCL Input Capacitance
SYMBOL
f
SCL
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
HD:DAT
t
SU:DAT
t
SU:STA
t
R
t
F
t
SU:STO
C
BIN
(Note 8)
(Note 7)
(Note 7)
CONDITIONS
MIN
0
1.3
0.6
1.3
0.6
0
100
0.6
20 +
0.1C
B
20 +
0.1C
B
0.6
10
300
300
0.9
TYP
MAX
400
UNITS
kHz
Fs
Fs
Fs
Fs
Fs
ns
Fs
ns
ns
Fs
pF
Note 1:
Limits are 100% tested at T
A
= +25°C and T
A
= +85°C. Limits over the operating temperature range and relevant supply
voltage range are guaranteed by design and characterization. Typical values are not guaranteed.
Note 2:
Includes the temperature conversion current (averaged).
Note 3:
Does not include
RST
leakage if V
CC
< V
PF
.
Note 4:
The parameter t
OSF
is the period of time the oscillator must be stopped for the OSF flag to be set.
Note 5:
The state of
RST
does not affect the I
2
C interface or RTC functions.
Note 6:
Interface timing shown is for fast-mode (400kHz) operation. This device is also backward-compatible with standard mode
I
2
C timing.
Note 7:
C
B
= total capacitance of one bus line in picofarads.
Note 8:
Guaranteed by design and not 100% production tested.
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