DS12885

Real Time Clock Overview

The DS12885 is a real-time clock and calendar IC designed as a direct replacement for the DS1285 and DS1287. It provides timekeeping in HH:MM:SS (12/24 hour) format and YY-MM-DD-dd date format, with automatic adjustments for month lengths and leap years. The device includes one time-of-day alarm, three maskable interrupts, a programmable square wave output, and 114 bytes of battery-backed static RAM. It operates on a 4.5V to 5.5V supply with a 2.5V to 4V backup input, switching automatically upon primary power failure. The component is housed in a 24-PDIP package.

Real Time Clock Feature Summary

• Integrated 114-byte battery-backed NVSRAM
• Automatic leap year and date adjustment
• One time-of-day alarm and three maskable interrupts
• Programmable square wave output

Real Time Clock Applications

• Industrial control systems requiring precise timekeeping
• Data logging equipment needing non-volatile memory
• Telecommunications infrastructure monitoring

Real Time Clock Procurement Notes

Verify the specific suffix against the datasheet to confirm temperature range and package variations. Confirm RoHS compliance status for the exact ordering part number. Check for obsolescence notices or PCN documents from Analog Devices regarding this series. Ensure the backup voltage source matches the 2.5V to 4V specification.

Real Time Clock Selection Notes

Select this component when a parallel interface RTC with integrated SRAM is required. Compare the 114-byte capacity against application data storage needs. Verify that the system can support the 15mA maximum current draw during active operation. Ensure the 24-DIP footprint fits the target PCB layout constraints.

Real Time Clock Part Context

The DS12885 belongs to the Maxim Integrated RTC family, serving as a successor to the DS1285/DS1287. It is distinct from the DS12C887, which adds a century byte at address 32h. The DS12887 variant integrates a quartz crystal and lithium energy source within the package, whereas the standard DS12885 requires external components for these functions.

Real Time Clock Replacement Considerations

The M48T86MH1E is listed as an available substitute. Verify pin compatibility and feature parity before implementation.