DS12885S

Overview

The DS12885S is a real-time clock and calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It provides timekeeping in either 12-hour or 24-hour format with an AM/PM indicator, alongside date tracking that automatically adjusts for month lengths and leap years. The device includes 114 bytes of battery-backed static RAM (NVSRAM) and features one time-of-day alarm, three maskable interrupts, and a programmable square wave output. It operates on a primary supply of 4.5V to 5.5V with a maximum current consumption of 15mA during timekeeping. A precision temperature-compensated circuit monitors Vcc status to ensure automatic switching to a backup supply upon primary power failure.

Feature Summary

• Integrated real-time clock/calendar with automatic leap year correction
• 114 bytes of non-volatile static RAM (NVSRAM)
• One time-of-day alarm and three maskable interrupts
• Programmable square wave output

Applications

• Computer systems requiring persistent timekeeping
• Industrial control equipment needing accurate scheduling
• Data logging devices with power loss protection

Procurement Notes

Verify the specific package variant when ordering, as the DS12885S series includes both SOIC and PLCC packages. Confirm the operating temperature range requirements against the specific suffix (e.g., S for commercial vs. Q for industrial). Ensure compatibility with the system's parallel bus interface timing specifications before procurement.

Selection Notes

Select the DS12885S for applications requiring a direct replacement for legacy DS1285/DS1287 RTCs with added NVSRAM. Choose this component if a parallel interface is preferred over serial alternatives. Verify that the 4.5V to 5.5V supply voltage aligns with the host system's logic levels and that the 24-pin SOIC footprint fits the PCB layout constraints.

Part Context

The DS12885S belongs to the DS12885 family of real-time clocks designed to replace older DS1285 and DS1287 models. This family integrates quartz crystal and lithium energy sources in some variants, though the DS12885S specifically utilizes external components or internal circuitry depending on the exact revision. It shares functional similarities with the DS12887 and DS12C887, differing primarily in package type and century byte availability.

Replacement Considerations

The DS1685S-5+ is listed as a similar substitute part number for discontinued variants within this product line.