real-time clock (RTC) with an integrated temperature-
compensated crystal oscillator (TCXO) and crystal.
The device incorporates a battery input, and maintains
accurate timekeeping when main power to the device
is interrupted. The integration of the crystal resonator
enhances the long-term accuracy of the device as well
as reduces the piece-part count in a manufacturing line.
The DS3231 is available in commercial and industrial
temperature ranges, and is offered in a 16-pin, 300-mil
SO package.
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 programmable square-wave 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 necessary.
Additionally, the
RST
pin is monitored as a pushbutton
input for generating a μP reset.
●
Highly Accurate RTC Completely Manages All
Timekeeping Functions
• Real-Time Clock Counts Seconds, Minutes, Hours,
Date of the Month, Month, Day of the Week, and
Year, with Leap-Year Compensation Valid Up to 2100
• Accuracy ±2ppm from 0°C to +40°C
• Accuracy ±3.5ppm from -40°C to +85°C
• Digital Temp Sensor Output: ±3°C Accuracy
• Register for Aging Trim
•
RST
Output/Pushbutton Reset Debounce Input
• Two Time-of-Day Alarms
• Programmable Square-Wave Output Signal
●
Simple Serial Interface Connects to Most
Microcontrollers
• Fast (400kHz) I
2
C Interface
●
Battery-Backup Input for Continuous Timekeeping
• Low Power Operation Extends Battery-Backup
Run Time
• 3.3V Operation
●
Operating Temperature Ranges: Commercial
(0°C to +70°C) and Industrial (-40°C to +85°C)
●
Underwriters Laboratories
®
(UL) Recognized
●
Servers
●
Telematics
Applications
●
Utility Power Meters
●
GPS
Typical Operating Circuit
V
CC
R
PU
= t
R
/C
B
R
PU
SCL
P
SDA
RST
PUSHBUTTON
RESET
V
CC
R
PU
SCL
SDA
RST
N.C.
N.C.
N.C.
N.C.
Ordering Information and Pin Configuration appear at end of data
sheet.
V
CC
V
CC
INT/SQW
32kHz
V
BAT
N.C.
N.C.
N.C.
GND
N.C.
DS3231
Underwriters Laboratories is a registered certification mark of
Underwriters Laboratories Inc.
19-5170; Rev 10; 3/15
DS3231
Extremely Accurate I
2
C-Integrated
RTC/TCXO/Crystal
Absolute Maximum Ratings
Voltage Range on Any Pin Relative to Ground ....-0.3V to +6.0V
Junction-to-Ambient Thermal Resistance (θ
JA) (Note 1)73°C/W
Junction-to-Case Thermal Resistance (θ
JC) (Note 1) ....23°C/W
Operating Temperature Range
DS3231S ............................................................0°C to +70°C
DS3231SN ...................................................... -40°C to +85°C
Junction Temperature ......................................................+125°C
Storage Temperature Range .............................. -40°C to +85°C
Lead Temperature (soldering, 10s) ................................. +260°C
Soldering Temperature (reflow, 2 times max) ................. +260°C
(see the
Handling, PCB Layout, and Assembly
section)
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
www.maximintegrated.com/thermal-tutorial.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation 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
= T
MIN
to T
MAX
, unless otherwise noted.) (Notes 2, 3)
PARAMETER
Supply Voltage
Logic 1 Input SDA, SCL
Logic 0 Input SDA, SCL
SYMBOL
V
BAT
V
IH
V
IL
V
CC
CONDITIONS
MIN
2.3
2.3
0.7 x
V
CC
-0.3
TYP
3.3
3.0
MAX
5.5
5.5
V
CC
+
0.3
0.3 x
V
CC
UNITS
V
V
V
V
Electrical Characteristics
PARAMETER
Active Supply Current
(V
CC
= 2.3V to 5.5V, V
CC
= Active Supply (see Table 1), T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Typical values are at V
CC
=
3.3V, V
BAT
= 3.0V, and T
A
= +25°C, unless otherwise noted.) (Notes 2, 3)
SYMBOL
I
CCA
(Notes 4, 5)
CONDITIONS
V
CC
= 3.63V
V
CC
= 5.5V
MIN
TYP
MAX
200
300
110
170
575
650
2.45
2.575
2.70
0.4
0.4
-1
-1
RST
high impedance (Note 6)
-200
25
0
+1
+1
+10
100
UNITS
µA
Standby Supply Current
I
CCS
I
2
C bus inactive, 32kHz
V
CC
= 3.63V
output on, SQW output off
V
CC
= 5.5V
(Note 5)
V
CC
= 3.63V
I
2
C bus inactive, 32kHz
output on, SQW output off V
CC
= 5.5V
I
OL
= 3mA
I
OL
= 1mA
Output high impedance
µA
Temperature Conversion Current
Power-Fail Voltage
Logic 0 Output, 32kHz,
INT/SQW,
SDA
Logic 0 Output,
RST
Output Leakage Current 32kHz,
INT/SQW,
SDA
Input Leakage SCL
RST
Pin I/O Leakage
V
BAT
Leakage Current
(V
CC
Active)
I
CCSCONV
V
PF
V
OL
V
OL
I
LO
I
OL
I
BATLKG
I
LI
µA
V
V
V
µA
µA
µA
nA
www.maximintegrated.com
Maxim Integrated
│
2
DS3231
Extremely Accurate I
2
C-Integrated
RTC/TCXO/Crystal
Electrical Characteristics (continued)
(V
CC
= 2.3V to 5.5V, V
CC
= Active Supply (see Table 1), T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Typical values are at V
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