I2C Interface and low time keeping voltage RTC

The PT7C4337 serial real-time clock is a low-power clock/calendar with two programmable time-of-day alarms and a programmable square-wave output. 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 device is fully accessible through the serial interface while VCC is between 1.8V and 5.5V. I2C operation is not guaranteed below 1.8V. Timekeeping operation is maintained with VCC as low as 1.2V.

• Using external 32.768kHz quartz crystal for PT7C4337
• Supports I2C-Bus"s 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
• Two Time-of-Day Alarms
• Oscillator Stop Flag
• Operating range: 1.8V to 5.5V
• Timekeeping range: 1.2V to 1.8V