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 into a 24-pin encapsulated DIP (EDIP) package. The device provides a multiplexed byte-wide interface for accessing timekeeping functions and extended battery-backed NV SRAM. It supports optional +3.0V or +5.0V operation, with a supply voltage range of 2.7V to 3.7V for the -3 suffix variant. Key features include automatic leap year compensation through 2099, power-control circuitry for system wake-up, and a 64-bit silicon serial number.

Real Time Clock Feature Summary

• Integrates quartz crystal and lithium battery in EDIP-24 package
• Provides 8192 bytes of extended battery-backed NV SRAM
• Supports system power-on via date/time alarm or key closure
• Includes 64-bit silicon serial number and SMI recovery stack

Real Time Clock Applications

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

Real Time Clock Procurement Notes

Verify the specific ordering suffix '-3+' indicates the +3.0V operating voltage range (2.7V to 3.7V) and RoHS compliance. Confirm the EDIP-24 package availability and lead times with authorized distributors, as this component may have limited stock due to its specialized integrated battery design.

Real Time Clock Selection Notes

Select the DS17887-3+ when 8KB of nonvolatile RAM is required alongside RTC functionality. Ensure the system operates within the 2.7V to 3.7V VCC range. For applications requiring external crystals, consider the DS17885 series instead. Verify that the multiplexed bus interface matches the host microcontroller's timing requirements.

Real Time Clock Part Context

The DS17887 belongs to the DS17x87 family, which are successors to the industry-standard DS12887 PC clock. Unlike the DS17x85 series, the DS17x87 devices integrate the oscillator and power source directly into the package, simplifying board layout and reducing component count for embedded designs.

Real Time Clock Replacement Considerations

The DS12887 is the legacy predecessor but lacks integrated components and extended RAM. The DS17885S-3+ offers similar functionality in an SO-24 package but requires an external crystal and battery.