DS17487-3+

Real Time Clock Overview

The DS17487-3+ is a real-time clock (RTC) module from the DS17x87 series, designed as a successor to the DS12887. It integrates a quartz crystal and lithium energy source within a 24-pin encapsulated DIP (EDIP) package. The device provides a multiplexed byte-wide interface for accessing timekeeping functions and 4096 bytes of battery-backed nonvolatile SRAM. It supports both +3.0V and +5.0V operation with automatic power-fail detection and switching. Key features include leap year compensation through 2099, a silicon serial number, and programmable interrupt outputs.

Real Time Clock Feature Summary

• Integrated EDIP Package: Combines RTC logic, 32.768kHz crystal, and lithium battery in a single 24-pin DIP form factor.
• Extended Memory: Includes 4096 bytes of battery-backed NV SRAM plus 114 bytes of general-purpose RAM.
• Power Control: Features wake-up alarm and kickstart capabilities via PWR and KS pins for system power management.
• Timekeeping Accuracy: Factory-trimmed to ±1 minute per month at 25°C with automatic leap year correction through 2099.

Real Time Clock Applications

• Embedded Systems
• Utility Meters
• Security Systems
• Network Hubs, Bridges, and Routers

Real Time Clock Procurement Notes

Verify component authenticity and physical condition upon receipt. Confirm that the EDIP package integrity remains intact, as internal lithium cells are sensitive to mechanical stress or soldering temperatures exceeding specified limits. Ensure compatibility with existing board layouts requiring 24-pin DIP footprints.

Real Time Clock Selection Notes

Select this model when an integrated solution eliminating external crystals and batteries is required. The -3 suffix indicates +3.0V VCC operation; verify against system voltage requirements (+3.0V vs +5.0V). Consider the EDIP package constraints regarding hand or wave-soldering only, avoiding reflow processes that may damage the internal energy source.

Real Time Clock Part Context

This component belongs to the DS17x87 family, which includes DS17287, DS17487, and DS17887 variants differing primarily by NV SRAM capacity (2KB, 4KB, and 8KB respectively). These devices succeed the industry-standard DS12887 PC clock, offering enhanced features such as silicon serial numbers and advanced power control circuitry while maintaining pin compatibility.

Real Time Clock Replacement Considerations

Direct replacements within the same family include DS17287-3+ (2KB SRAM) and DS17887-3+ (8KB SRAM), provided memory requirements align. For surface-mount applications, consider the DS17485S-5+ variant, though it requires external crystal and battery components and utilizes a SOIC package.