DS1553P-85+

Real Time Clock Overview

The DS1553P-85+ is a Year-2000-compliant real-time clock/calendar integrated with 64KB nonvolatile static RAM. It operates at a nominal 5V supply within a commercial temperature range of 0°C to +70°C. The device utilizes a parallel interface and features double-buffered RTC registers for accurate timekeeping up to the year 2100. Key functions include an alarm, watchdog timer, power-on reset, and battery monitoring. Data retention exceeds 10 years via an internal lithium source that connects upon first power application.

Real Time Clock Feature Summary

• Integrated 64KB NV SRAM with RTC registers mapped to the top 16 memory locations
• Parallel byte-wide interface with automatic leap year compensation
• Programmable watchdog timer and RTC alarm with interrupt output
• Power-fail write protection and precision power-on reset circuitry

Real Time Clock Applications

• Industrial systems requiring reliable timekeeping and data storage
• Embedded controllers needing backup memory and system supervision
• Equipment requiring Y2K compliance and long-term data retention

Real Time Clock Procurement Notes

Verify the specific suffix 'P-85+' corresponds to the 34-pin PowerCap module configuration rather than the standard 28-pin DIP package. Confirm that the separate DS9034PCX PowerCap component is included or ordered separately, as it houses the crystal and lithium battery required for operation. Check current availability status as this component may be subject to end-of-life restrictions.

Real Time Clock Selection Notes

Select the DS1553P-85+ when a parallel interface and large onboard nonvolatile memory are required alongside timekeeping functions. Ensure the design accommodates the 34-pin PowerCap module footprint and allows for post-reflow mounting of the external PowerCap unit. Verify that the 5V logic levels and parallel bus architecture align with the host microcontroller's capabilities.

Real Time Clock Part Context

This part belongs to the Maxim Integrated DS1553 family of timekeeping RAM devices. The 'P' designation indicates the PowerCap module format, which separates the silicon from the energy source during soldering. The '+85' suffix denotes the 5V voltage variant with a commercial temperature rating. This series provides a consolidated solution for RTC and NVSRAM needs in legacy and industrial designs.

Real Time Clock Replacement Considerations

Direct replacements must match the 34-pin PowerCap form factor and parallel interface. Verify compatibility with the DS9034PCX PowerCap accessory. Cross-reference pinouts and register maps if substituting with other RTC/NVRAM combinations.