DS12885TN

Real Time Clock Overview

The DS12885TN is a real-time clock and calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It provides timekeeping for seconds, minutes, hours, day, date, month, and year with leap year compensation through 2099. The device includes 114 bytes of battery-backed static RAM and supports both 12-hour and 24-hour formats. It operates on a 4.5V to 5.5V supply with a 2.5V to 4V battery backup range. The unit features automatic power-fail detection and switching, ensuring continuous operation during primary power loss.

Real Time Clock Feature Summary

• Direct replacement for IBM AT computer clock/calendar systems
• Includes 114 bytes of general-purpose battery-backed NVSRAM
• Supports selectable Intel or Motorola bus timing interfaces
• Features one time-of-day alarm and three maskable interrupts

Real Time Clock Applications

• IBM AT compatible computer systems
• Industrial control systems requiring precise timekeeping
• Data logging equipment with battery backup requirements

Real Time Clock Procurement Notes

Verify the 32-TQFP package configuration and -40°C to 85°C industrial temperature grade against specific design requirements. Confirm that the parallel interface compatibility matches the target system's bus architecture before procurement.

Real Time Clock Selection Notes

Select this component when a drop-in replacement for legacy DS1285/DS1287 designs is required in a surface-mount TQFP package. Ensure the system can accommodate the 4.5V to 5.5V VCC supply and provides adequate space for the 32-pin footprint.

Real Time Clock Part Context

This part belongs to the DS12885 family, designed as successors to the industry-standard DS1285 and DS1287. While other variants like the DS12887 integrate crystals and batteries, the DS12885TN relies on external components for these functions but offers enhanced interrupt and alarm capabilities within a compact TQFP form factor.

Real Time Clock Replacement Considerations

The DS12885TN serves as a direct pin-compatible replacement for the DS1285 and DS1287. Designers upgrading from older DIP packages must account for the transition to the 32-TQFP surface-mount format.