DS1685-5-IND

Real Time Clock Overview

The DS1685-5-IND is a real-time clock (RTC) IC from Analog Devices/Maxim Integrated, operating at +5V with an industrial temperature range of -40°C to +85°C. It features a multiplexed address/data bus interface and provides timekeeping for years through 2099, including leap-year compensation. The device integrates 242 bytes of battery-backed NV SRAM, a 64-bit silicon serial number, and power-control circuitry for system wake-up via alarm or kickstart input. Key pins include PWR for power-on control, SQW for square-wave output, and IRQ for interrupt requests.

Real Time Clock Feature Summary

• Industrial temperature grade (-40°C to +85°C) with +5V operation
• 242 bytes of battery-backed NV SRAM with bank switching
• Y2K compliant with leap-year compensation valid through 2099
• Power-control circuitry supports system power-on from date/time alarm or key closure

Real Time Clock Applications

• Embedded systems requiring precise timekeeping
• Utility meters needing nonvolatile data storage
• Security systems with alarm-based wake-up capabilities
• Network hubs, bridges, and routers

Real Time Clock Procurement Notes

Verify the specific package type required, as the DS1685 family includes PDIP, SO, TSSOP, PLCC, and EDIP variants. Confirm that the -5 suffix indicates the +5V supply version and IND denotes the industrial temperature range. Ensure compatibility with existing BIOS software if replacing legacy DS1287 components. Check for lead-free/RoHS compliance markings on the top mark.

Real Time Clock Selection Notes

Select this component when a +5V RTC with industrial temperature stability is required. The multiplexed bus interface suits systems with limited I/O lines. Consider the DS1687 if an integrated crystal and battery solution is preferred over discrete components. Verify that the external crystal load capacitance matches the CS bit setting in Extended Control Register 4Bh.

Real Time Clock Part Context

The DS1685 series serves as a successor to industry-standard DS1285, DS1385, DS1485, and DS1585 PC RTCs. It maintains compatibility with original DS1287 functions while adding enhanced features like a silicon serial number and auxiliary battery input. The -IND suffix specifically identifies the industrial temperature variant within the broader DS1685 product line.

Real Time Clock Replacement Considerations

Direct replacement for DS1287-compatible designs. Verify pinout compatibility for PDIP, SO, or TSSOP packages. For lead-free requirements, ensure the ordering suffix includes '+'. Industrial temperature versions are available with 'IND' or 'N' suffixes depending on the package.