DS14285+

Real Time Clock Overview

The DS14285+ is a real-time clock (RTC) with nonvolatile RAM control, designed as a direct replacement for IBM AT computer clocks. It features a multiplexed address/data bus interface and provides timekeeping for seconds through years, including leap year compensation valid to 2100. The device includes 114 bytes of general-purpose RAM and 14 bytes of clock/control registers, accessible via software as 128 locations. It supports binary or BCD data formats, 12/24-hour modes, and daylight saving time adjustments. Operating at +5V with a +3V battery backup, it ensures data retention during power failures.

Real Time Clock Feature Summary

• Direct replacement for IBM AT clock/calendar with DS1287 compatibility
• Multiplexed bus interface supporting Intel timing mode
• Automatic write protection and external SRAM nonvolatile control
• Three software-maskable interrupts: alarm, periodic, and update-ended

Real Time Clock Applications

• IBM AT compatible computer systems
• Industrial equipment requiring precise timekeeping
• Data logging systems with nonvolatile memory requirements

Real Time Clock Procurement Notes

Verify the specific package variant required, as the base model number covers multiple pin configurations including DIP-24 and SOIC-24. Confirm temperature grade specifications, noting that standard versions operate from 0°C to +70°C while industrial grades extend to -40°C to +85°C. Ensure the ordering suffix matches the desired physical footprint and operating range before procurement.

Real Time Clock Selection Notes

Select the DS14285+ when an Intel-compatible multiplexed bus interface is required for system integration. Choose this component over the DS14287 if an external quartz crystal and separate battery source are preferred or already present in the design. Consider the industrial temperature variant (DS14285N+) if operation below 0°C is necessary.

Real Time Clock Part Context

The DS14285+ belongs to the Dallas Semiconductor RTC family, now under Analog Devices. It functions alongside variants like the DS14287, which integrates the battery and crystal internally. This component specifically targets legacy PC architectures and embedded systems needing robust timekeeping with additional nonvolatile storage capabilities controlled by the chip's internal power management logic.

Real Time Clock Replacement Considerations

The DS14285+ is functionally compatible with the DS1287. For industrial temperature applications, the DS14285N+ serves as the equivalent high-temperature grade replacement. Systems requiring integrated battery solutions may consider the DS14287 series instead.