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 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.

FEATURES ƒ

♦  Real-Time Clock (RTC) Counts Seconds,

    Minutes, Hours, Date of the Month, Month,

    Day of the week, and Year with Leap-Year

    Compensation Valid Up to 2100 ƒ

♦  56-Byte, Battery-Backed, Nonvolatile (NV)

    RAM for Data Storage ƒ

♦  I²C Serial Interface ƒ

♦  Programmable Square-Wave Output Signal

♦ ƒ Automatic Power-Fail Detect and Switch Circuitry

♦ ƒ Consumes Less than 500nA in Battery-

    Backup Mode with Oscillator Running

♦ ƒ Optional Industrial Temperature Range:

    -40°C to +85°C

♦ ƒ Available in 8-Pin Plastic DIP or SO

♦ ƒ Underwriters Laboratory (UL) Recognized

TIMING DIAGRAM