DS1557WP-120IND+

Real Time Clock Overview

The DS1557WP-120IND+ is a Y2K-compliant real-time clock and calendar integrated with 512k x 8 nonvolatile static RAM. It operates on a 3.3V supply within an industrial temperature range of -40°C to +85°C. The device features a parallel interface, 34-pin PowerCap module packaging, and includes an internal lithium battery for data retention exceeding 10 years without power. Key functions include BCD-coded timekeeping, programmable alarms, watchdog timers, and automatic leap year compensation.

Real Time Clock Feature Summary

• Integrated RTC, 512KB NV SRAM, crystal, and lithium battery in a single module
• Y2K compliant with automatic leap year correction valid through 2100
• Programmable watchdog timer and alarm with interrupt output
• Power-fail write protection and precision power-on reset

Real Time Clock Applications

• Industrial systems requiring precise timekeeping during power outages
• Data logging equipment needing nonvolatile storage for timestamps
• Embedded controllers utilizing watchdog timer functionality
• Battery-backed memory modules for critical system state preservation

Real Time Clock Procurement Notes

Verify the specific voltage rating (3.3V vs 5V) and temperature grade (commercial vs industrial) when sourcing replacements. Confirm that the required PowerCap base (DS9034PCX+) is ordered separately as it is not included with the module. Ensure compatibility with existing parallel bus architectures.

Real Time Clock Selection Notes

Select this component for applications requiring high-density nonvolatile memory combined with accurate timekeeping. The 3.3V variant is suitable for low-voltage systems, while the industrial grade ensures reliability in harsh environments. Consider the 34-pin PowerCap form factor for board space constraints and ease of replacement.

Real Time Clock Part Context

This part belongs to the DS1557 family of nonvolatile timekeeping RAMs. It shares architectural similarities with the DS1556 and DS1747 series but offers larger memory capacity. The 'WP' suffix indicates the 3.3V operating voltage, while 'IND' denotes the extended industrial temperature range.

Real Time Clock Replacement Considerations

Direct substitutes include other DS1557 variants with different voltage or temperature ratings. For pin-compatible alternatives, consider the DS1556W series if lower memory capacity is acceptable. Verify that any replacement supports the same parallel interface and PowerCap package dimensions.