GENERAL DESCRIPTION
The DS1307 serial real-time clock (RTC) is a lowpower, full binary-coded decimal (BCD) clock/calendar
plus 56 bytes of NV SRAM. Address and data are
transferred serially through an I2
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
o I2C Serial Interface
 Low Power Operation Extends Battery Backup Run Time
o Consumes Less than 500nA in BatteryBackup 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