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 NV SRAM, crystal, and lithium energy source. It operates at 3.3V with a 120ns access time in the commercial temperature range (0°C to +70°C). The device uses a standard JEDEC byte-wide 32k x 8 static RAM pinout via a 28-pin EDIP module. RTC registers reside in the top eight RAM locations, storing BCD-coded century, year, month, date, day, hours, minutes, and seconds with automatic leap-year compensation valid through 2100.

Real Time Clock Feature Summary

• Integrated 32k x 8 NV SRAM with RTC registers in the uppermost memory locations
• Y2K-compliant BCD calendar/clock with automatic leap-year compensation valid to 2100
• Internal lithium battery backup ensures over 10 years of data retention without power
• Power-fail write protection circuitry prevents data corruption during voltage outages

Real Time Clock Applications

• Industrial control systems requiring precise timekeeping and nonvolatile storage
• Data logging equipment needing reliable timestamping capabilities
• Embedded systems utilizing standard parallel SRAM interfaces for RTC integration

Real Time Clock Procurement Notes

Verify the specific suffix W-120 indicates the 3.3V commercial grade variant. Confirm package type matches the 28-pin EDIP module requirement. Check RoHS compliance status if lead-free specifications are mandatory for the assembly process. Ensure the design accommodates the through-hole mounting style specified for this component.

Real Time Clock Selection Notes

Select the DS1744W-120 when a 3.3V supply is available and the commercial temperature range suffices. Choose the IND+ variant for industrial environments (-40°C to +85°C). Consider the PowerCap version if surface-mount assembly constraints require separating the battery/crystal module from the silicon base. Verify interface compatibility with the standard 32k x 8 SRAM pinout.

Real Time Clock Part Context

This component belongs to the DS174x family of timekeeping RAMs, offering pin-for-pin compatibility across different densities. It combines the functionality of a standalone RTC and NV SRAM into a single package, simplifying board layout by eliminating separate components for timekeeping and battery-backed memory.

Real Time Clock Replacement Considerations

Pin-for-pin compatible with other densities in the DS174x series. Verify voltage requirements (3.3V vs 5V) and temperature ranges when substituting with variants like DS1744-70 or DS1744P models.