DS17885S-5

Real Time Clock Overview

The DS17885S-5 is a real-time clock (RTC) integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It provides timekeeping functions including seconds, minutes, hours, day, date, month, and year with automatic leap-year compensation through 2099. The device features an 8KB battery-backed NV SRAM, one time-of-day alarm, three maskable interrupts, and a programmable square-wave output. It operates on a multiplexed byte-wide interface and supports optional +3.0V or +5.0V supply voltages. The component includes power-control circuitry for system wake-up and a 64-bit silicon serial number.

Real Time Clock Feature Summary

• Real-time clock/calendar with leap-year correction through 2099
• 8KB battery-backed nonvolatile SRAM
• Multiplexed byte-wide address/data bus interface
• Power-control circuitry supporting system power-on via alarm or key closure

Real Time Clock Applications

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

Real Time Clock Procurement Notes

Verify the specific voltage variant required for the design, as the suffix indicates the operating voltage range (+5V). Confirm package availability, as this component may be discontinued or subject to limited supply conditions. Ensure the selected part matches the required temperature range and that the ordering suffix corresponds exactly to the intended electrical specifications.

Real Time Clock Selection Notes

Select the DS17885S-5 when 8KB of battery-backed memory is required alongside standard RTC functionality. This model is suitable for designs needing a multiplexed parallel interface rather than serial alternatives. Consider the DS17887 if an encapsulated DIP package with an integrated crystal and lithium battery source is preferred over external components.

Real Time Clock Part Context

The DS17885 series serves as a successor to the industry-standard DS12885 and DS12887 devices. It enhances the original architecture by incorporating a silicon serial number, extended battery-backed NV SRAM options (2k, 4k, or 8k bytes), and improved power-control circuitry. The S-5 designation specifically denotes the SOIC package variant optimized for +5.0V operation.

Real Time Clock Replacement Considerations

The DS12885 is a direct predecessor compatible with many pinouts but lacks the enhanced features like the silicon serial number and extended RAM options found in the DS17885 series.