DS1744W-120+

Real Time Clock Overview

The DS1744W-120+ is a Y2K-compliant, nonvolatile timekeeping RAM integrating a real-time clock/calendar (RTC), 32k x 8 static RAM, crystal, and lithium energy source. Operating at 3.3V with a 120ns access time, it features BCD-coded registers for century, year, month, date, day, hours, minutes, and seconds, including automatic leap-year compensation valid through 2100. The device provides over 10 years of data retention without power and includes power-fail write protection. It utilizes a standard JEDEC byte-wide interface where RTC registers occupy the top eight RAM locations.

Real Time Clock Feature Summary

• Integrated NV SRAM, RTC, crystal, and lithium battery in a single 28-pin EDIP module
• Y2K-compliant with automatic leap-year compensation valid up to the year 2100
• Over 10 years of data retention in the absence of VCC power
• Power-fail write protection allows for ±10% VCC power-supply tolerance

Real Time Clock Applications

• Systems requiring precise timekeeping and nonvolatile data storage
• Industrial equipment needing Y2K compliance
• Embedded systems with limited board space for discrete RTC components

Real Time Clock Procurement Notes

Verify the specific voltage requirement, as the DS1744 series includes both 5.0V and 3.3V variants. Confirm the package type matches the design, as this model uses the 28-pin EDIP DIP module which integrates the crystal and battery internally. Ensure the ordering suffix corresponds to the required temperature range and RoHS compliance status.

Real Time Clock Selection Notes

Select the DS1744W-120+ for applications requiring a 3.3V supply and 120ns access speed. For 5.0V systems or faster 70ns access times, consider the DS1744-70+ variant. If surface-mount compatibility with a separate PowerCap module is preferred over an integrated DIP solution, evaluate the DS1744P series instead.

Real Time Clock Part Context

This component belongs to the DS174x family of timekeeping RAMs from Analog Devices/Maxim Integrated. It is pin-for-pin compatible with other densities in the DS174x series, allowing for design flexibility across different memory requirements while maintaining the same RTC functionality and interface.

Real Time Clock Replacement Considerations

The DS1744W-120IND+ serves as the industrial temperature grade replacement (-40°C to +85°C). For 5.0V operation, the DS1744-70+ offers equivalent functionality with faster access speeds.