DS17885S-3+

Real Time Clock Overview

The DS17885S-3+ is a real-time clock (RTC) IC from the DS17x85 family, manufactured by Analog Devices Inc./Maxim Integrated. It provides timekeeping for seconds through years with leap year compensation through 2099. The device features an optional +3.0V operation range (2.7V to 3.7V VCC) and includes 8192 bytes of battery-backed NV SRAM in addition to standard registers. It utilizes a multiplexed byte-wide interface and incorporates power-control circuitry for system wake-up functions.

Real Time Clock Feature Summary

• Real-time clock/calendar with automatic date adjustment and leap year correction through 2099
• 8192 bytes of extended battery-backed NV SRAM plus 114 bytes of general-purpose RAM
• +3.0V operation mode with VCC supply range of 2.7V to 3.7V
• Power-control circuitry supporting system power-on via date/time 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 suffix '-3' confirms the 2.7V–3.7V operating range rather than the standard 5V variant. Confirm package type is SOIC-24. Check manufacturer documentation for current production status as older RTC models may have limited availability.

Real Time Clock Selection Notes

Select this part when 8KB of nonvolatile storage is required alongside RTC functionality. Ensure the application supports the multiplexed address/data bus interface. Verify that the external crystal matches the specified load capacitance requirements for the oscillator circuit.

Real Time Clock Part Context

This component belongs to the DS17x85 series, designed as successors to the industry-standard DS12885 and DS12887. The 'S' indicates a SOIC package, while the '-3+' suffix denotes the 3V operation option and lead-free compliance.

Real Time Clock Replacement Considerations

DS17885E-5+

Real Time Clock FAQ

How does the device handle primary power failure?

A precision temperature-compensated circuit monitors VCC. If primary power fails, the device automatically switches to the backup supply (VBAT or VBAUX) to maintain time and data.

What is the function of the KS pin?

The KS pin is an active-low kickstart input that can trigger the PWR output to power on the system when VCC is removed, provided VBAUX is present and the auxiliary-battery-enable bit is set.

Can the clock operate in both 12-hour and 24-hour formats?

Yes, the device operates in either 24-hour or 12-hour format with an AM/PM indicator in the 12-hour mode.