PT7C433833AUEX

Real Time Clock Overview

The PT7C433833AUEX is a discontinued Real-Time Clock (RTC) module manufactured by Diodes Incorporated, packaged in an 8-pin MSOP. It operates on a 2-wire I2C serial interface with a maximum clock frequency of 400 kHz. The device provides timekeeping for seconds, minutes, hours, days, dates, months, and years, supporting both 12-hour and 24-hour formats. It includes 56 bytes of non-volatile RAM and features a programmable square wave output at frequencies of 1 Hz, 4.096 kHz, 8.192 kHz, or 32.768 kHz. Electrical specifications include a supply voltage range of 2.7 V to 5.5 V and a battery backup range of 1.3 V to 3.7 V.

Real Time Clock Feature Summary

• Integrated oscillator designed for a 32.768 kHz crystal with internal load capacitance of 20 pF per pin.
• Built-in power-fail detection circuit that automatically switches between main supply (VCC) and battery backup (VBAT).
• Oscillator Stop Flag (OSF) bit indicates when the clock has stopped due to power failure.
• Supports standard and fast mode I2C communication up to 400 kHz.

Real Time Clock Applications

• Embedded systems requiring precise timekeeping and calendar functions.
• Data logging equipment needing non-volatile memory retention during power loss.
• Consumer electronics utilizing low-power real-time clock modules.

Real Time Clock Procurement Notes

This component is officially marked as PART OBSOLETE and DISCONTINUED by Diodes Incorporated. Verification of availability should focus on distributor surplus stock rather than direct manufacturing orders. Sourcing requires confirmation of lot dates and storage conditions due to the discontinuation status.

Real Time Clock Selection Notes

Designers must account for the specific package dimensions of the 8-pin Mini Small Outline Package (MSOP). The device requires external pull-up resistors on the SDA and SQW/OUT lines. Ensure the connected crystal matches the specified 12.5 pF load capacitance for accurate timing.

Real Time Clock Part Context

The PT7C433833AUEX belongs to the PT7C433833A series from Diodes Incorporated. The 'U' suffix specifically denotes the 8-pin MSOP package variant, distinguishing it from the SOIC ('W') and TDFN ('ZE') versions within the same functional family.

Real Time Clock Replacement Considerations

As this part is discontinued, engineers should evaluate alternative RTC ICs from current product lines. Verify compatibility regarding I2C address, register mapping, and physical footprint if selecting a direct pin-compatible substitute.

Real Time Clock FAQ

How does the device handle power transitions?

The PT7C433833AUEX includes a power-fail detection circuit. When VCC drops below the power-fail threshold (VPF), the device automatically switches to the VBAT input to maintain timekeeping and data retention without interruption.

What are the available square wave output frequencies?

The SQW/OUT pin can be programmed to output square waves at four distinct frequencies: 1 Hz, 4.096 kHz, 8.192 kHz, or 32.768 kHz, controlled via the Rate Select bits in the Control Register.

Is the oscillator stop flag reset automatically?

No, the Oscillator Stop Flag (OSF) bit in the Control Register is set when the oscillator stops. It must be cleared manually by software after the oscillator is restarted and stable.