DS1746WP-120IND

Real Time Clock Overview

The DS1746WP-120IND is a Y2K-compliant, nonvolatile timekeeping RAM featuring a 128k x 8 static RAM array and an integrated real-time clock/calendar. Operating at 3.3V with an industrial temperature range of -40°C to +85°C, it utilizes a 34-pin PowerCap module package for surface-mount assembly. The device integrates a lithium energy source, crystal, and power-fail control circuitry. Clock registers reside in the top eight RAM locations, accessed via a standard JEDEC byte-wide interface. It provides automatic leap year compensation valid through 2100 and includes battery voltage-level monitoring.

Real Time Clock Feature Summary

• Integrated NV SRAM (128k x 8), RTC, crystal, and lithium battery source in a single 34-pin PowerCap module.
• Y2K-compliant with BCD-coded century, year, month, date, day, hours, minutes, and seconds.
• Automatic leap year compensation valid up to the year 2100.
• Power-fail write protection ensures data integrity during supply voltage fluctuations.

Real Time Clock Applications

• Industrial systems requiring precise timekeeping without external components.
• Data logging equipment needing nonvolatile storage with calendar functions.
• Embedded controllers utilizing standard SRAM interfaces for RTC access.

Real Time Clock Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm lead-free status and temperature grade. Confirm that the separate DS9034PCX+ or DS9034I-PCX+ PowerCap unit is included or ordered separately, as the DS1746WP-120IND base module requires this external component for full functionality.

Real Time Clock Selection Notes

Select the DS1746WP-120IND for surface-mount designs requiring industrial temperature operation (-40°C to +85°C) and 3.3V logic levels. Ensure compatibility with the 34-pin PowerCap footprint. For through-hole applications, consider the DIP variant instead. Verify that the system design accommodates the separate mounting of the PowerCap battery module after soldering to protect the internal lithium source from reflow temperatures.

Real Time Clock Part Context

This component belongs to the DS174xP family of nonvolatile timekeeping RAMs. It is pin-compatible with other densities in the series, such as the DS1746P-70IND+, allowing for density upgrades within the same form factor. The 'W' suffix denotes the PowerCap module package, while 'IND' indicates the industrial temperature range.

Real Time Clock Replacement Considerations

Pin-for-pin compatible with other DS174xP series devices like the DS1746P-70IND+. Verify voltage requirements (3.3V vs 5V) when substituting with other family members.

Real Time Clock FAQ

How is the lithium battery connected in the DS1746WP-120IND?

The DS1746WP-120IND is a module board designed for direct connection to a separate PowerCap unit (such as DS9034PCX+). The PowerCap contains the lithium battery and crystal and is mounted on top of the module after surface mount processing.

What is the expected data retention time for this device?

The device is guaranteed to retain data and keep time for over 10 years at 25°C in the absence of VCC power, provided the internal clock oscillator is running.

How does the device handle power failures?

The DS1746WP-120IND includes a power-fail control circuit that disables write operations when VCC drops below a specific threshold (VPF). It automatically switches power to the backup lithium source to maintain RTC and SRAM data.