General Description
The HT1380/HT1381 is a serial timekeeper IC which provides seconds, minutes, hours, day, date, month and year information. The number of days in each month and leap years are automatically adjusted. The HT1380/HT1381 is designed for low power consumption and can operate in two modes: one is the 12-hour mode with an AM/PM indicator, the other is the 24-hour mode.

FEATUREs
• Operating voltage: 2.0V~5.5V
• Maximum input serial clock: 500kHz at VDD=2V, 2MHz at VDD=5V
• Operating current: less than 400nA at 2V, less than 1.2 μA at 5V
• TTL compatible
   - VIH: 2.0V~VDD+0.3V at VDD=5V
   - VIL: -0.3V~+0.8V at VDD=5V
• Two data transmission modes: single-byte, or burst mode
• Serial I/O transmission
• All registers store BCD format
• HT1380: 8-pin DIP package
   HT1381: 8-pin SOP package

APPLICATIONs
• Microcomputer serial clock
• Clock and Calendar