Diodes Incorporated
Back to Real Time Clock (RTC)


I2C Interface with 56Byte NVRAM RTC

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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. Table 1 shows the basic functions of PT7C4307. More details are shown in section: overview of functions.


  • Using external 32.768kHz quartz crystal
  • 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
  • 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

Product Specifications

Product Parameters

Compliance(Only Automotive supports PPAP) Standard
Time Display 12, 24
NV Ram 56x8
Interface I2C
Alarm Interrupt 0
Battery Backup 1
Clock Calibration 0

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Product Change Notices (PCNs)

A PCN may only apply to specific orderable part numbers in this datasheet. Please refer to the corresponding PCN to see the exact orderable part number(s) affected.

PCN # Issue Date Implementation Date Subject
PCN-2642 2023-09-05 2024-03-05 Device End of Life (EOL)
PCN-2505 2021-01-26 2021-07-26 Device End of Life (EOL)