DS1746P-70IND+

Real Time Clock Overview

The DS1746P-70IND+ is a Y2K-compliant real-time clock (RTC) and 128k x 8 nonvolatile static RAM integrated into a 34-pin PowerCap module. Operating at 5V with an industrial temperature range of -40°C to +85°C, it features a byte-wide parallel interface compatible with standard JEDEC SRAM pinouts. The device integrates the RTC logic, crystal, lithium energy source, and power-fail control circuitry within the module base. Clock 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, RTC, crystal, and lithium battery source in a single surface-mountable module.
• Y2K compliant with automatic leap year compensation valid through 2100.
• Power-fail write protection ensures data integrity during supply voltage fluctuations.
• Lithium energy source electrically disconnected until first power application to preserve freshness.

Real Time Clock Applications

• Industrial systems requiring precise timekeeping without external components.
• Data logging equipment needing nonvolatile storage for timestamps.
• Embedded controllers requiring backup memory and calendar functions.

Real Time Clock Procurement Notes

Verify that the separate DS9034PCX+ or DS9034I-PCX+ PowerCap unit is ordered, as it is required for operation but shipped separately. Confirm the specific IND suffix indicates the industrial temperature grade (-40°C to +85°C). Ensure the design accommodates the 34-pin PowerCap module board footprint and allows for post-reflow mounting of the PowerCap unit.

Real Time Clock Selection Notes

Select this model for applications requiring surface mount assembly where high-temperature soldering must not damage the internal crystal or battery. Unlike the DIP variant, the PowerCap design allows the battery module to be mounted after reflow. Ensure the system operates at 5V; for 3.3V systems, consider the DS1746W series. Verify compatibility with the DS9034PCX+ PowerCap accessory.

Real Time Clock Part Context

This component belongs to the DS1746/DS1746P family of Y2K-compliant nonvolatile timekeeping RAMs. It is functionally equivalent to other densities in the DS174x series regarding pinout and register mapping, allowing for potential density upgrades in designs using the same interface. The 'P' designation specifically denotes the PowerCap package style distinct from the encapsulated DIP modules.

Real Time Clock Replacement Considerations

Direct pin-for-pin replacements within the same package style include other densities of the DS174xP series. For different voltage requirements, the DS1746WP-120IND+ serves as a 3.3V alternative. Cross-package substitution with the DS1746-70IND+ requires redesigning the PCB for a 32-pin EDIP footprint rather than the 34-pin PowerCap layout.