Product Description
The PT7C4307 serial real-time clock is a low-power clock/calendar with a programmable square-wave output and 56 bytes of nonvolatile RAM.
Address and data are transferred serially via a 2-wire, bidirectional bus. The clock/calendar 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 PT7C4307 has a built-in power sense circuit that detects power failures and automatically switches to the battery supply.

Product Features
• Using external 32.768kHz quartz crystal
• Supports I2C-Buss high speed mode (400 kHz)
• Includes time (Hour/Minute/Second) and calendar (Year/Month/Date/Day) counter functions (BCD code)
• Programmable square wave output signal
• 56-byte, battery-backed, nonvolatile (NV) RAM for data storage
• Automatic power-fail detect and switch circuitry of battery backup
• Consumes less than 500nA in battery backup mode with oscillator running