PT7C4339WEX

Real Time Clock Overview

The PT7C4339 is a low-power Real-Time Clock (RTC) module manufactured by Diodes Incorporated. It provides timekeeping and calendar functions including seconds, minutes, hours, day, date, month, and year with leap-year compensation valid until 2100. The device communicates via an I2C serial interface supporting high-speed mode up to 400 kHz. It features two programmable time-of-day alarms, a programmable square-wave output, and automatic power-fail detection with switching to a backup supply. The PT7C4339 operates within a temperature range of -40°C to +85°C and is available in MSOP-8L and SOIC-8L packages.

Real Time Clock Feature Summary

• I2C Serial Interface: Supports high-speed mode (400 kHz) for data transfer.
• Calendar Functions: BCD code counters for time and date with automatic leap-year adjustment through 2100.
• Power Management: Built-in power-fail detect circuit automatically switches to VBACKUP to maintain operation.
• Alarms and Output: Two time-of-day alarms and a programmable square-wave output (1 Hz to 32.768 kHz).

Real Time Clock Applications

• Consumer electronics requiring accurate timekeeping
• Industrial systems needing battery-backed clock/calendar
• Embedded devices utilizing I2C communication

Real Time Clock Procurement Notes

Verify package type availability as the PT7C4339 is offered in MSOP-8L and SOIC-8L. Confirm that external 32.768 kHz crystals are sourced separately, as this variant does not integrate the oscillator. Ensure VBACKUP supply voltage remains between 1.3V and 3.7V for proper operation. Check datasheet for specific ordering suffixes corresponding to tape-and-reel or tube packaging.

Real Time Clock Selection Notes

Select the PT7C4339 when an external crystal is preferred or required for specific frequency tolerance. Compare against the PT7C4339C if an integrated crystal solution is desired to simplify PCB layout. Ensure the application supports I2C pull-up requirements on SDA and SCL lines. Verify that the operating voltage range of 3.0V to 5.5V matches the system design.

Real Time Clock Part Context

The PT7C4339 belongs to the PT7C43xx series of real-time clock modules from Diodes Incorporated. It is functionally similar to the PT7C4339C but requires an external 32.768 kHz crystal connected to X1 and X2 pins. This distinction allows designers to choose between component count reduction (PT7C4339C) or external crystal specification flexibility (PT7C4339).

Real Time Clock Replacement Considerations

The PT7C4339C is a direct pin-compatible alternative that integrates the crystal. Other variants in the PT7C43xx family may share register maps but differ in package or oscillator integration. Verify electrical characteristics and pinout compatibility before substitution.