DS1746-70+

Real Time Clock Overview

The DS1746-70+ is a Y2K-compliant, nonvolatile timekeeping RAM integrating a real-time clock/calendar and 128k x 8 static RAM. It operates at 5V with a commercial temperature range of 0°C to +70°C in a 32-pin EDIP package. The device features BCD-coded time registers with automatic leap year compensation up to 2100. Clock registers reside in the top eight RAM locations and are accessed via a standard byte-wide parallel interface. It includes integrated power-fail write protection, a lithium energy source for over 10 years of data retention, and a battery voltage-level indicator flag.

Real Time Clock Feature Summary

• Integrated NV SRAM, RTC, crystal, power-fail control circuit, and lithium energy source
• Y2K compliant with century byte register and automatic leap year compensation valid to 2100
• Standard JEDEC pinout compatible with 128k x 8 static RAMs
• Power-fail write protection allows ±10% VCC supply tolerance

Real Time Clock Applications

• Industrial systems requiring precise timekeeping without external batteries
• Data logging equipment needing nonvolatile storage with calendar functions
• Embedded controllers requiring Y2K compliance and long-term data retention

Real Time Clock Procurement Notes

Verify the specific suffix indicates the commercial temperature grade (0°C to +70°C) rather than the industrial variant (-40°C to +85°C). Confirm the package type is the 32-pin EDIP module, which integrates the crystal and battery internally. Ensure compatibility with 5V logic levels as specified for this part number.

Real Time Clock Selection Notes

Select the DS1746-70+ when a 5V supply is available and commercial temperature operation suffices. For industrial environments (-40°C to +85°C), choose the DS1746-70IND+. If surface mount assembly is required with a separate PowerCap module, consider the DS1746P-70+ series instead.

Real Time Clock Part Context

This component belongs to the DS174x family of nonvolatile timekeeping RAMs. It offers pin-for-pin compatibility with other densities in the series, allowing for density upgrades without redesigning the PCB layout. The DS1746 specifically provides 128KB of memory, distinguishing it from lower-density variants like the DS1743.

Real Time Clock Replacement Considerations

The DS1746-70IND+ serves as the direct industrial temperature grade replacement. For surface-mount applications, the DS1746P-70+ is the equivalent using a separate PowerCap module.