Low-Current I²C RTC with 56-Byte NV RAM

The DS1308 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV RAM. Address and data are transferred serially through an I²C interface. 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 an AM/PM indicator. The DS1308 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply, maintaining time and date operation.

Applications

* Consumer Electronics (Set-Top Box, Digital Recording, Network Appliance) * Handhelds (GPS, POS Terminal) * Medical (Glucometer, Medicine Dispenser) * Office Equipment (Fax/Printer, Copier) * Other (Utility Meter, Vending Machine, Thermostat, Modem) * Telecommunications (Router, Switcher, Server)

* Compatible with Crystal ESR Up to 100kΩ Allows a Crystal to be Optimized for Cost and Space

* Low-Power Operation Extends Battery Backup Run Time

* Low Timekeeping Current of 250nA (typ)

* Automatic Power-Fail Detect and Switch Circuitry

* 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 2400

* External Clock Source for Synchronization Clock Reference (e.g., 32kHz, 50Hz/60Hz Powerline, GPS 1PPS)

* 56-Byte, Battery-Backed, General-Purpose RAM with Unlimited Writes

* Programmable Square-Wave Output Signal

* Simple Serial Port Interfaces with Most Microcontrollers

* I2C Serial Interface

* Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications

* Underwriters Laboratories (UL®) Recognized