64 x 8, Serial, I
2
C Real-Time Clock
GENERAL DESCRIPTION
The DS1307 serial real-time clock (RTC) is a low-
power, full binary-coded decimal (BCD) clock/calendar
plus 56 bytes of NV SRAM. Address and data are
2
transferred serially through an I C, bidirectional bus.
The clock/calendar provides seconds, minutes, hours,
day, date, month, and year information. The end of
the month date 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 AM/PM indicator. The DS1307 has a
built-in power-sense circuit that detects power failures
and automatically switches to the backup supply.
Timekeeping operation continues while the part
operates from the backup supply.
BENEFITS AND FEATURES
Completely Manages All Timekeeping Functions
o
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
o
56-Byte, Battery-Backed, General-Purpose
RAM with Unlimited Writes
o
Programmable Square-Wave Output Signal
Simple Serial Port Interfaces to Most
Microcontrollers
2
o
I C Serial Interface
Low Power Operation Extends Battery Backup
Run Time
o
Consumes Less than 500nA in Battery-
Backup Mode with Oscillator Running
o
Automatic Power-Fail Detect and Switch
Circuitry
8-Pin DIP and 8-Pin SO Minimizes Required
Space
Optional Industrial Temperature Range: -40°C to
+85°C Supports Operation in a Wide Range of
Applications
Underwriters Laboratories® (UL) Recognized
TYPICAL OPERATING CIRCUIT
V
CC
V
CC
CRYSTAL
V
CC
R
PU
R
PU
X1
SCL
X2
V
CC
SQW/OUT
CPU
SDA
V
BAT
GND
R
PU
= t
r
/C
b
PIN CONFIGURATIONS
TOP VLEW
X1
X2
V
BAT
GND
SO (150 mils)
V
CC
SQW/OUT
SCL
SDA
X1
X2
V
BAT
GND
PDIP (300 mils)
V
CC
SQW/OUT
SCL
SDA
ORDERING INFORMATION
PART
TEMP RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
VOLTAGE (V)
5.0
5.0
5.0
5.0
5.0
5.0
PIN-PACKAGE
8 PDIP (300 mils)
8 PDIP (300 mils)
8 SO (150 mils)
8 SO (150 mils)
8 SO (150 mils) Tape and Reel
8 SO (150 mils) Tape and Reel
TOP MARK*
+Denotes
a lead-free/RoHS-compliant package.
*A
“+” anywhere on the top mark indicates a lead-free package. An “N” anywhere on the top mark indicates an industrial temperature range device.
Underwriters Laboratories, Inc. is a registered certification mark of Underwriters Laboratories, Inc.
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