DS17887-5

Real Time Clock Overview

The DS17887-5+ is a real-time clock (RTC) from the DS17x87 series, manufactured by Analog Devices Inc./Maxim Integrated. It integrates a quartz crystal and lithium energy source within a 24-pin encapsulated DIP (EDIP) package. The device provides timekeeping for seconds, minutes, hours, day, date, month, and year with automatic leap-year compensation through 2099. It features 8192 bytes of battery-backed nonvolatile SRAM, a time-of-day alarm, and six maskable interrupts. The unit operates on a +5.0V supply (4.5V to 5.5V range) and utilizes a multiplexed byte-wide interface for data access.

Real Time Clock Feature Summary

• Integrated EDIP Package: Combines RTC functionality with an internal quartz crystal and lithium battery in a 24-pin DIP form factor.
• Extended Memory: Includes 8192 bytes of battery-backed NV SRAM alongside standard 114 bytes of general-purpose RAM.
• Power Control Circuitry: Supports system power-on via external stimuli or wake-up alarms using the PWR output pin.
• Automatic Calendar Adjustment: Handles month length variations and leap years automatically through 2099.

Real Time Clock Applications

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

Real Time Clock Procurement Notes

Verify the specific suffix (+) indicates lead-free compliance when sourcing. Confirm the EDIP package availability as this variant contains integrated passive components that may have specific handling requirements during assembly. Check current distribution status as older Maxim Integrated products may have limited availability or require alternative sourcing channels.

Real Time Clock Selection Notes

Select the DS17887-5+ when a self-contained RTC solution with significant nonvolatile memory is required without external crystal or battery components. Ensure the design supports the +5V logic levels and multiplexed bus interface. Consider the industrial temperature range options if operation outside the commercial 0°C to +70°C range is necessary.

Real Time Clock Part Context

This component belongs to the DS17x87 family, designed as successors to the industry-standard DS12887. Unlike the DS17x85 variants which require external crystals and batteries, the DS17x87 series encapsulates these elements directly into the package. This integration simplifies PCB layout and reduces component count for applications requiring robust timekeeping and data retention.

Real Time Clock Replacement Considerations

The DS12887+ serves as a functional predecessor but lacks the extended SRAM capacity and enhanced power-control features found in the DS17887-5+. Direct pin-compatible replacement is possible, but software adjustments are required to utilize the additional memory banks and interrupt flags.