DS17485S-3

Real Time Clock Overview

The DS17485S-3 is a real-time clock (RTC) IC from the DS17x85 family, designed as a successor to the industry-standard DS12885. It provides timekeeping for seconds, minutes, hours, day, date, month, and year with leap-year compensation through 2099. The device features a multiplexed byte-wide interface, 4096 bytes of extended battery-backed NV SRAM, and 114 bytes of general-purpose RAM. It supports optional +3.0V or +5.0V operation, includes a silicon serial number, and offers power-control circuitry for system wake-up via alarm or kickstart input.

Real Time Clock Feature Summary

• Multiplexed byte-wide address/data bus interface
• 4096 bytes of extended battery-backed NV SRAM plus 114 bytes user RAM
• Leap-year compensation valid through 2099
• Integrated 64-bit silicon serial number

Real Time Clock Applications

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

Real Time Clock Procurement Notes

Verify the specific suffix 'S' indicates the SOIC package variant when sourcing replacements. Confirm voltage grade compatibility (+3V vs +5V) as electrical characteristics differ between variants. Check RoHS compliance status if environmental regulations apply to the target assembly process.

Real Time Clock Selection Notes

Select this component for designs requiring a direct pin-compatible upgrade from legacy DS12885 RTCs with added nonvolatile memory. Ensure the host system supports multiplexed bus timing requirements. Verify that the external crystal load capacitance matches the device's selectable 6pF or 12.5pF configuration.

Real Time Clock Part Context

This part belongs to the Maxim Integrated DS17x85 series, which serves as an enhanced replacement for the Dallas Semiconductor DS12885/DS12887 lines. The 'S' suffix denotes the surface-mount SOIC package option, distinguishing it from the PDIP or EDIP (integrated battery/crystal) packages available in the same functional family.

Real Time Clock Replacement Considerations

Direct functional substitutes include other parts within the DS17285, DS17485, and DS17885 families, differentiated by SRAM capacity and package type. Ensure the replacement maintains the required voltage range and interrupt logic levels.