Supports High-ESR Crystals Up to 100kΩ to Allow Crystals to be Optimized for Cost and Space
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 2200
Two Time-of-Day Alarms
Programmable Square-Wave Output Signal
Low-Power Operation Extends Battery Backup Run Time
Automatic Power-Fail Detect and Switch Circuitry
Simple Serial Port Interfaces to Most Microcontrollers
I2C Serial Interface
Underwriters Laboratories (UL®) Recognized
DS1339B Applications
Consumer Electronics (Set-Top Box, Digital Recording, Network Appliance)
Handhelds (GPS, POS Terminals)
Medical (Glucometer, Medicine Dispenser)
Office Equipment (Fax/Printers, Copier)
Other (Utility Meter, Vending Machine, Thermostat, Modem)
Telecommunications (Routers, Switches, Servers)
DS1339B Description
The DS1339B serial real-time clock (RTC) is a low-power clock/date device with two programmable time-of-day alarms and a programmable square-wave output. Address and data are transferred serially through an I²C bus. The clock/date provides 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 AM/PM indicator. The device has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply, maintaining time, date, and alarm operation.
