Diodes Incorporated
Back to Real Time Clock (RTC)


I2C interface with 56Byte NVRAM RTC

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Product Description

The PT7C4311 serial real-time clock is a low-power clock/calendar with 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 the 24- hour format indicator.

Table 1 shows the basic functions of PT7C4311. More details are shown in section: overview of functions. 


  • Support I2C-Bus (High speed mode 400kHz)

  • Includes time (Hour/Minute/Second) and calendar (Century/Year/Month/Date/Day) counter functions

  • Year 2000 compliant

  • Automatic switch-over and deselect circuitry

  • Time keeping voltage: 1.2V to 5.5V

  • Software clock calibration

  • 56 bytes of general purpose RAM

  • Ultra-low battery supply current of 0.3μA

  • Low operating current of 70μA

  • Battery or super cap back-up

  • Operating temperature: -40°C to 85°C

  • Automatic leap year compensation

  • Special software programmable output 

Product Specifications

Product Parameters

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

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Additional Technical Documents are available upon request:
Application information, Evaluation board, and Other technical documents

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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-2510 2021-02-26 2021-05-26 Qualified Additional A/T Sites, Fab Site and Data Sheet Change
PCN-2505 2021-01-26 2021-07-26 Device End of Life (EOL)