DS1556WP-120

Real Time Clock Overview

The DS1556WP-120 is a nonvolatile, year-2000-compliant real-time clock/calendar integrated with 128k x 8 static RAM. It operates at 3.3V and features a 34-pin PowerCap module package. The device includes an internal lithium energy source for over 10 years of data retention without power. Key functions include a programmable watchdog timer, RTC alarm, precision power-on reset, and battery voltage monitoring. Clock registers are accessed via the top 16 RAM locations using a byte-wide parallel interface.

Real Time Clock Feature Summary

• Integrated NV SRAM (128KB), RTC, crystal, and lithium battery in one module
• Y2K compliant with automatic leap-year compensation up to 2100
• Programmable watchdog timer and RTC alarm with interrupt output
• Precision power-on reset and battery voltage-level indicator flag

Real Time Clock Applications

• Embedded systems requiring precise timekeeping and nonvolatile storage
• Industrial control units needing watchdog protection
• Battery-backed memory applications with low power requirements

Real Time Clock Procurement Notes

Verify the specific ordering suffix against the manufacturer's current datasheet to confirm temperature range and RoHS compliance status. The PowerCap module requires a separate DS9034PCX component for full assembly. Ensure the system design accommodates the 34-pin PowerCap footprint and associated mounting constraints.

Real Time Clock Selection Notes

Select this model for 3.3V systems requiring surface-mount assembly with integrated battery backup. Compare with the DS1556W-120 if a 32-pin DIP package is preferred instead of the PowerCap module. Verify that the required operating temperature range matches the commercial or industrial grade specifications listed in the ordering information.

Real Time Clock Part Context

This component belongs to the DS1556 family of nonvolatile timekeeping RAM devices. It shares functional similarities with other models in the series but differs in package type and supply voltage. The PowerCap variant allows for post-solder reflow mounting of the battery module, protecting sensitive components during assembly.

Real Time Clock Replacement Considerations

Direct replacements within the same family include the DS1556WP-120IND+ for industrial temperature ranges. Other variants like the DS1556P-70+ offer different voltage levels and packages. Verify pin compatibility and electrical characteristics before substitution.