Rev 2; 6/05
Extremely Accurate I
2
C-Integrated
RTC/TCXO/Crystal
General Description
The DS3231 is a low-cost, extremely accurate I
2
C real-
time clock (RTC) with an integrated temperature-
compensated crystal oscillator (TCXO) and crystal. The
device incorporates a battery input, and maintains accu-
rate timekeeping when main power to the device is inter-
rupted. 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 refer-
ence 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 nec-
essary. Additionally, the
RST
pin is monitored as a
pushbutton input for generating a reset externally.
Features
♦
Accuracy ±2ppm from 0°C to +40°C
♦
Accuracy ±3.5ppm from -40°C to +85°C
♦
Battery Backup Input for Continuous
Timekeeping
♦
Operating Temperature Ranges
Commercial: 0°C to +70°C
Industrial: -40°C to +85°C
♦
Low-Power Consumption
♦
Real-Time Clock Counts Seconds, Minutes,
Hours, Day, Date, Month, and Year with Leap Year
Compensation Valid Up to 2100
♦
Two Time-of-Day Alarms
♦
Programmable Square-Wave Output
♦
Fast (400kHz) I
2
C Interface
♦
3.3V Operation
♦
Digital Temp Sensor Output: ±3°C Accuracy
♦
Register for Aging Trim
♦
RST
Input/Output
♦
UL Recognized
DS3231
Ordering Information
PART
DS3231S
DS3231SN
DS3231S+
DS3231SN+
TEMP RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
16 SO
16 SO
16 SO
16 SO
TOP
MARK
DS3231
DS3231N
DS3231+
DS3231N+
Applications
Servers
Telematics
Utility Power Meters
GPS
Pin Configuration appears at end of data sheet.
+Denotes lead-free
Typical Operating Circuit
V
CC
V
CC
R
PU
= t
R
/C
B
R
PU
R
PU
V
CC
SCL
CPU
SDA
RST
PUSHBUTTON
RESET
N.C.
N.C.
N.C.
N.C.
INT/SQW
32kHz
V
BAT
N.C.
N.C.
N.C.
N.C.
V
CC
DS3231
GND
Purchase of I
2
C components from Maxim Integrated Products, Inc., or one of its sublicensed Associated Companies, conveys a
license under the Philips I
2
C Patent Rights to use these components in an I
2
C system, provided that the system conforms to the I
2
C
Standard Specification as defined by Philips.
______________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
DALLAS [ DALLAS SEMICONDUCTOR ]
