DS1685S-5

Real Time Clock Overview

The DS1685S-5 is a real-time clock (RTC) IC in a 24-SOIC package. It operates on a +5V supply and includes 242 bytes of battery-backed NV SRAM. The device supports multiplexed parallel interfaces, providing timekeeping with leap-year compensation through 2099. Key features include Y2K compliance, a 32kHz square-wave output, power-control circuitry for system wake-up, and a 64-bit silicon serial number. It maintains time via an external 32.768kHz crystal and auxiliary battery inputs.

Real Time Clock Feature Summary

• Incorporates industry-standard DS1287 PC clock functions with enhanced Y2K compliance
• Provides 242 bytes of battery-backed non-volatile RAM accessible during update cycles
• Supports system power-on from date/time alarms or keyboard kickstart events
• Includes a 32kHz square-wave output for power management activities

Real Time Clock Applications

• Embedded systems requiring precise timekeeping
• Utility meters needing data retention during power loss
• Security systems with alarm logging capabilities
• Network hubs, bridges, and routers

Real Time Clock Procurement Notes

Verify component authenticity as the DS1685S-5 may be discontinued. Confirm RoHS compliance status and check for lead-free alternatives like the DS1685S-5+ if required by current manufacturing standards. Ensure compatibility with existing BIOS implementations for original DS1287 functions.

Real Time Clock Selection Notes

Select this model for applications requiring a +5V primary supply and parallel interface. Ensure the design accommodates external 32.768kHz crystals with specified load capacitances. Verify that the 24-SOIC package dimensions fit the PCB layout constraints and that sufficient NV SRAM space meets storage requirements.

Real Time Clock Part Context

The DS1685 series serves as a successor to earlier Dallas Semiconductor RTC models like the DS1285 and DS1385. It integrates standard PC clock functionality with additional features such as extended RAM and power control. The S-5 suffix denotes the surface-mount SOIC package variant operating at 5 volts within the commercial temperature range.

Real Time Clock Replacement Considerations

Direct substitutes include the DS1685S-5+T&R. For industrial temperature ranges, consider the DS1685EN-5+ variants. Check datasheet revisions to ensure pinout and register compatibility with legacy designs.