DS1685-3

Real Time Clock Overview

The DS1685-3+ is a real-time clock (RTC) integrated circuit designed for +3.0V operation within the DS1685 family. It provides industry-standard DS1287 PC clock functionality with Y2K compliance and leap-year compensation valid through 2099. The device features a multiplexed address/data bus interface, 242 bytes of battery-backed NV SRAM, and a 64-bit silicon serial number. Key electrical parameters include a supply voltage range of 2.7V to 3.7V and an operating temperature range of 0°C to +70°C. It incorporates power-control circuitry for system wake-up via alarm or kickstart input.

Real Time Clock Feature Summary

• Y2K compliant timekeeping with leap-year compensation valid through 2099
• 242 bytes of user-accessible nonvolatile RAM divided into two banks
• +3.0V primary supply operation with auxiliary battery inputs (VBAT/VBAUX)
• Integrated power-on control allowing system activation via date/time alarm or key closure

Real Time Clock Applications

• Embedded systems requiring precise timekeeping
• Utility meters for data logging and billing cycles
• Security systems needing event timestamping
• Network hubs, bridges, and routers for synchronization

Real Time Clock Procurement Notes

Verify that the specific order suffix matches the required package type, as the base model DS1685-3 corresponds to the 24-pin PDIP variant. Confirm the voltage suffix indicates the +3.0V version (+3) rather than the +5.0V version (+5). Ensure the presence of the '+' symbol confirms lead-free/RoHS compliance status. Check manufacturer documentation for any updates regarding component availability or lifecycle status changes.

Real Time Clock Selection Notes

Select the DS1685-3+ when a +3.0V primary supply is available and a 24-pin PDIP package is preferred for through-hole mounting. This variant is suitable for commercial temperature applications ranging from 0°C to +70°C. For industrial temperature ranges (-40°C to +85°C), consider the DS1685EN-3+ variant instead. Ensure the design supports the multiplexed bus interface requirements for address and data lines.

Real Time Clock Part Context

The DS1685 series serves as a successor to earlier industry-standard RTCs like the DS1285 and DS1385. It integrates enhanced features such as a silicon serial number and advanced power management compared to its predecessors. The device is manufactured by Analog Devices Inc./Maxim Integrated and is part of a broader family including variants with different voltages, packages, and temperature grades.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers are not explicitly listed in the provided datasheet for this specific component.