DS1685SN-5+T&R

Real Time Clock Overview

The DS1685SN-5+T&R is a real-time clock (RTC) IC manufactured by Analog Devices Inc./Maxim Integrated. It operates with a +5V supply voltage and supports an industrial temperature range of -40°C to +85°C. The device features a multiplexed address/data bus interface and includes 242 bytes of battery-backed NV SRAM. Key specifications include a 64-bit silicon serial number, Y2K compliance, and leap-year compensation valid through 2099. It is housed in a 24-pin TSSOP package and supplied in tape and reel format.

Real Time Clock Feature Summary

• Incorporates industry-standard DS1287 PC clock functions with enhanced features such as Y2K compliance and a 64-bit silicon serial number.
• Provides 242 bytes of user-accessible nonvolatile RAM divided into two banks (114 bytes in Bank 0 and 128 extended bytes in Bank 1).
• Features power-control circuitry allowing system power-on via date/time alarm or kickstart input (KS pin).
• Includes a 32kHz square-wave output for power management activities and supports auxiliary battery input.

Real Time Clock Applications

• Embedded Systems
• Utility Meters
• Security Systems
• Network Hubs, Bridges, and Routers

Real Time Clock Procurement Notes

Verify the ordering suffix 'T&R' confirms the Tape & Reel packaging format. Confirm the 'SN' designation corresponds to the SOIC/TSSOP package style and the '-5+' indicates +5V operation with lead-free/RoHS compliance. Check current availability status as this component may be subject to discontinuation or limited stock conditions.

Real Time Clock Selection Notes

Select this part for applications requiring a direct replacement for legacy DS1285/DS1287 RTCs with added NV RAM and wake-up capabilities. Ensure the design supports a multiplexed bus interface and provides a +5V primary supply with a 3V backup source. Verify that the TSSOP-24 package fits the PCB footprint constraints.

Real Time Clock Part Context

The DS1685 series serves as a successor to the Dallas Semiconductor DS1285, DS1385, DS1485, and DS1585. It maintains compatibility with existing BIOS implementations while adding modern features like silicon serialization and enhanced power management. The SN variant specifically denotes the surface-mount package option within the broader DS1685 family.

Real Time Clock Replacement Considerations

Direct substitutes include other DS1685 variants with different packages or temperatures, such as DS1685S-5+T&R (SOIC) or DS1685EN-5+T&R (Industrial Temp TSSOP). Cross-reference with DS1285/DS1287 equivalents if legacy compatibility without NV RAM expansion is sufficient.