DS1742W-120+

Real Time Clock Overview

The DS1742W-120+ is a Y2K-compliant real-time clock/calendar and 2k x 8 nonvolatile static RAM integrated into a single component. It operates at a supply voltage of 3.3V with a range of 2.97V to 3.63V, supporting an operating temperature from 0°C to +70°C. The device utilizes a standard JEDEC bytewide parallel interface compatible with static RAM pinouts. RTC registers are mapped to the eight top RAM locations and store century, year, month, date, day, hours, minutes, and seconds in BCD format. It includes automatic leap year compensation valid until 2100 and features internal lithium battery backup for over 10 years of data retention.

Real Time Clock Feature Summary

• Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit, and Lithium Energy Source
• Standard JEDEC Bytewide 2k x 8 Static RAM Pinout with Double-Buffered RTC Registers
• Automatic Leap Year Compensation Valid Up to the Year 2100
• Power-Fail Write Protection Allows for ±10% VCC Power Supply Tolerance

Real Time Clock Applications

• Systems requiring precise timekeeping and nonvolatile data storage without external components
• Industrial or commercial equipment needing Y2K compliance and battery-backed memory
• Embedded controllers utilizing standard parallel RAM interfaces for clock access

Real Time Clock Procurement Notes

Verify the specific suffix W-120+ indicates the 3.3V voltage variant and commercial temperature range (0°C to +70°C). Confirm RoHS compliance status via the '+' designation. Check current availability as this component may be subject to end-of-life restrictions or limited distribution channels.

Real Time Clock Selection Notes

Select the DS1742W-120+ when a 3.3V supply is required instead of the 5V variants. Ensure the system design accommodates the 24 EDIP package footprint. Verify that the parallel interface timing requirements align with the microcontroller's capabilities, specifically noting the 120ns to 150ns access times for the 3.3V version.

Real Time Clock Part Context

This part belongs to the DS1742 family of Y2KC Nonvolatile Timekeeping RAMs. It shares architectural similarities with the DS1742-100+ but differs in operating voltage (3.3V vs 5V) and temperature grade. The 'W' suffix typically denotes the wider voltage tolerance or specific voltage variant within the Maxim Integrated portfolio.

Real Time Clock Replacement Considerations

Direct replacements include other DS1742 series parts like DS1742W-150+ for identical electrical characteristics. For 5V applications, consider DS1742-100+. Cross-family replacements require verifying interface compatibility and voltage level shifting if necessary.