DS14285S+T&R

Real Time Clock Overview

The DS14285S+T&R is a real-time clock (RTC) and calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It operates within a commercial temperature range of 0°C to +70°C and requires a single +5V supply voltage. The device features a multiplexed address/data bus interface for pin-efficient connection to host processors. It provides timekeeping for seconds, minutes, hours, days, dates, months, and years with leap year compensation valid through the year 2100. The unit includes 114 bytes of general-purpose nonvolatile RAM controlled via external SRAM interfaces. It supports both binary and BCD data formats for time and calendar registers.

Real Time Clock Feature Summary

• Direct replacement for IBM AT computer clock/calendar functions
• Includes 114 bytes of nonvolatile static RAM control for external memory
• Multiplexed bus interface compatible with Intel and Motorola timing standards
• Programmable square wave output and three software-maskable interrupt sources

Real Time Clock Applications

• IBM AT compatible computer systems
• Industrial equipment requiring precise timekeeping and battery-backed memory
• Embedded systems needing nonvolatile data retention during power failures

Real Time Clock Procurement Notes

Verify that the specific ordering suffix matches the required temperature grade and packaging format. The 'S' indicates an SOIC package, while '+T&R' denotes lead-free/RoHS compliance in tape and reel packaging. Confirm compatibility with existing system bus timing requirements before procurement.

Real Time Clock Selection Notes

Select this component when a direct drop-in replacement for legacy IBM AT clock designs is required. Ensure the application utilizes a standard 32.768 kHz quartz crystal with a 6 pF load capacitance connected to X1 and X2 pins. Verify that the external SRAM data retention current requirements align with the internal lithium cell capacity if long-term backup is necessary.

Real Time Clock Part Context

This part belongs to the DS14285 family of real-time clocks with NVRAM control. It is functionally compatible with the earlier DS1285 and DS1287 models. The device distinguishes itself by integrating nonvolatile control logic for external SRAM, allowing standard CMOS static RAM to retain data during power outages without additional complex circuitry.

Real Time Clock Replacement Considerations

The DS1685S-5+ is listed as a similar replacement option for the discontinued DS14285S+ variant.