DS1340

DS1340 I2C RTC with Trickle Charger General Description The DS1340 is a real-time clock (RTC)/calendar that is pin compatible and functionally equivalent to the ST M41T00, including the software clock calibration. The device additionally provides trickle-charge capability on the VBACKUP pin, a lower timekeeping voltage, and an oscillator STOP flag. Block access of the register map is identical to the ST device. Two additional registers, which are accessed individually, are required for the trickle charger and flag. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. A built-in power-sense circuit detects power failures and automatically switches to the backup supply. Reads and writes are inhibited while the clock continues to run. The device is programmed serially through an I2C bidirectional bus. Applications Portable Instruments Point-of-Sale Equipment Medical Equipment Telecommunications Typical Operating Circuit VCC VCC CRYSTAL VCC RPU RPU 1 28 X1 6 SCL X2 VCC 7 FT/OUT CPU DS1340 5 SDA RPU = tR / CB 3 VBACKUP GND 4 C1 Pin Configurations appear at end of data sheet. UL is a registered trademark of Underwriters Laboratories Inc. Benefits and Features Enhanced Second Source for the ST M41T00 Completely Manages All Timekeeping Functions RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year Software Clock Calibration Oscillator Stop Flag Low-Power Operation Extends Battery Backup Run Time Low Tim...