DS17887-3

Real Time Clock Overview

The DS17887-3+ is a real-time clock (RTC) from Analog Devices/Maxim Integrated, 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 time, calendar, alarm, and control registers. It features automatic leap year compensation through 2099 and supports both 12-hour and 24-hour formats. The unit includes 8192 bytes of battery-backed nonvolatile SRAM and power-control circuitry that enables system wake-up via external stimuli or alarms.

Real Time Clock Feature Summary

• Integrated quartz crystal and lithium battery in a 24-pin EDIP package
• 8192 bytes of battery-backed NV SRAM with automatic power-fail switching
• Multiplexed byte-wide address/data bus interface
• Real-time clock/calendar with leap year compensation 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 by checking manufacturer markings against official datasheet specifications. Confirm the presence of the integrated lithium energy source and crystal within the EDIP housing. Ensure the ordering suffix matches the required voltage range (+3V operation). Check for RoHS compliance status if lead-free requirements are mandatory for the assembly process.

Real Time Clock Selection Notes

Select the DS17887-3+ when an integrated RTC solution with substantial nonvolatile memory is required without external components. The +3V variant operates between 2.7V and 3.7V on VCC. Compare storage capacity against other family members: DS17287 offers 2KB and DS17487 offers 4KB. Verify that the multiplexed bus interface timing aligns with the host processor's capabilities.

Real Time Clock Part Context

This component belongs to the DS17x87 series, which serves as an enhanced successor to the industry-standard DS12887. Unlike the DS17x85 variants that require external crystals and batteries, the DS17x87 family integrates these elements into the package. The DS17887 specifically provides the largest memory allocation within this integrated group, distinguishing it from the lower-capacity DS17287 and DS17487 models.

Real Time Clock Replacement Considerations

Direct pin-compatible replacements within the same family include the DS17287-3+ and DS17487-3+, though they offer reduced SRAM capacities of 2KB and 4KB respectively. Legacy equivalents such as the DS12887-3+ require external crystal and battery connections. Verify voltage compatibility and interface timing before substituting.