DS1374U-33

Real Time Clock Overview

The DS1374U-33 is a real-time clock (RTC) featuring a 32-bit binary counter for continuous timekeeping and an additional 24-bit counter configurable as a watchdog timer, alarm, or non-volatile RAM. It utilizes an I²C serial interface for programming and includes automatic power-fail detection with switching to a backup supply. The device operates within a voltage range of 2.97V to 5.50V and supports temperatures from -40°C to +85°C. Key features include separate interrupt and square-wave outputs, a pushbutton reset input, and trickle-charge capability for backup batteries.

Real Time Clock Feature Summary

• 32-bit binary counter for elapsed seconds and 24-bit secondary counter for alarms or NV RAM
• I²C serial interface supporting standard (100kHz) and fast mode (400kHz)
• Automatic power-fail detect and switch circuitry with open-drain reset output
• Programmable trickle charger for rechargeable backup supplies

Real Time Clock Applications

• Portable Instruments
• Point-of-Sale Equipment
• Medical Equipment
• Telecommunications

Real Time Clock Procurement Notes

Verify component authenticity through authorized distributors. Confirm the specific ordering suffix matches the required voltage variant (-33 indicates 3.3V operation). Check for RoHS compliance status and ensure the package type corresponds to the design requirements. Review the latest datasheet revision for any pinout or electrical characteristic updates before finalizing procurement.

Real Time Clock Selection Notes

Select the DS1374U-33 when a 3.3V nominal supply is available. Ensure the application requires a 32-bit time counter rather than a calendar format. Verify that the I²C bus speed requirements are compatible with the device's standard and fast modes. Consider the need for external crystals if using the U variant versus the integrated crystal in the C variant.

Real Time Clock Part Context

The DS1374U-33 belongs to the DS1374 family of RTCs manufactured by Analog Devices / Maxim Integrated. It shares functional similarities with other variants like the DS1374U-3 and DS1374U-18, differing primarily in operating voltage ranges. The 'U' designation indicates a 10-pin µSOP package without an integrated crystal, distinguishing it from the 'C' series which includes an onboard oscillator.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers: DS1374U-3, DS1374U-18.