DS12887A+

Real Time Clock Overview

The DS12887A+ is a real-time clock and calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It provides timekeeping functions including seconds, minutes, hours, day, date, month, and year with leap-year compensation up to the year 2099. The device features a multiplexed parallel bus interface supporting both Intel and Motorola modes. It includes 114 bytes of battery-backed static RAM for data storage. The unit integrates a quartz crystal and lithium energy source within a 24-pin EDIP package. Operating parameters include a supply voltage range of 4.5V to 5.5V and a maximum current consumption of 15mA at 5.5V.

Real Time Clock Feature Summary

• Integrated quartz crystal and lithium backup battery in a single 24-EDIP module
• Multiplexed parallel interface compatible with Intel and Motorola bus protocols
• 114 bytes of non-volatile SRAM for user data retention during power loss
• Automatic date adjustment for varying month lengths and leap years

Real Time Clock Applications

• Embedded systems requiring precise timekeeping
• Network hubs, bridges, and routers
• Security systems
• Electric meters
• IBM AT computer clock/calendar replacement

Real Time Clock Procurement Notes

Verify component authenticity through authorized distribution channels. Confirm RoHS compliance status as indicated in official documentation. Ensure the specific suffix matches design requirements. Check for restricted availability or discontinuation notices from the manufacturer before finalizing procurement plans.

Real Time Clock Selection Notes

Select this model when a direct parallel interface replacement for legacy DS1287 designs is required. The integrated battery and crystal simplify PCB layout compared to external oscillator solutions. Verify that the system supports multiplexed address/data buses. Consider the 24-EDIP through-hole package constraints for mechanical integration.

Real Time Clock Part Context

This component belongs to the DS12887 family designed to replace earlier DS1285 and DS1287 models. The 'A' suffix typically denotes an enhanced version within the series. The device shares functional similarities with the DS12C887A+, though the latter lacks the integrated crystal and battery found in the DS12887A+. Both utilize the same core RTC logic and RAM architecture.

Real Time Clock Replacement Considerations

The DS12887A+ serves as a direct pin-compatible replacement for the DS1287. Designers upgrading from older RTCs should verify software compatibility with the multiplexed bus timing. Alternative packages like PLCC are available for surface-mount applications but require different footprints.