DS1746W-120

Real Time Clock Overview

The DS1746W-120 is a Y2K-compliant, nonvolatile timekeeping RAM integrating a real-time clock/calendar and 128k x 8 static RAM. Operating at 3.3V with an industrial temperature range of -40°C to +85°C, it uses a standard JEDEC byte-wide interface. The device includes an integrated crystal, lithium energy source, and power-fail control circuit in a 32-pin EDIP package. RTC registers reside in the top eight RAM locations, providing century, year, month, date, day, hours, minutes, and seconds data in BCD format with automatic leap year compensation.

Real Time Clock Feature Summary

• Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit, and Lithium Energy Source
• Y2K Compliant with Century Byte Register and Automatic Leap Year Compensation Valid Up to 2100
• Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power
• Standard JEDEC Byte-Wide 128k x 8 Static RAM Pinout

Real Time Clock Applications

• Systems requiring Y2K-compliant timekeeping and nonvolatile data storage
• Industrial applications operating within -40°C to +85°C temperature ranges
• Equipment needing integrated battery backup for continuous clock operation

Real Time Clock Procurement Notes

Verify the specific ordering suffix to confirm voltage and temperature grade. The 'W' indicates 3.3V operation, while 'IND' denotes the industrial temperature range. Confirm RoHS compliance status via the '+' symbol in the part number. Ensure the 32-pin EDIP package matches the target PCB footprint requirements.

Real Time Clock Selection Notes

Select this component for designs requiring a combined RTC and large NVSRAM solution without external components. Compare against the 5V variants (DS1746-70) if system voltage differs. Consider the PowerCap module variant (DS1746P) if surface-mount assembly is preferred over through-hole DIP packaging.

Real Time Clock Part Context

The DS1746 series consists of Y2K-compliant, nonvolatile timekeeping RAMs. The DS1746W-120 specifically refers to the 3.3V version in the 32-pin encapsulated DIP package. It is pin-compatible with other densities in the DS174x family, allowing for design flexibility across different memory and voltage requirements.

Real Time Clock Replacement Considerations

Direct substitutes include other DS1746 variants with matching voltage and temperature ratings, such as DS1746W-120+ or DS1746W-120IND+. Verify package compatibility when replacing with the PowerCap module versions.