General Description The DS17285, DS17485, DS17885, DS17287, DS17487, and DS17887 real-time clocks (RTCs) are designed to be successors to the industry-standard DS12885 and DS12887. The DS17285, DS17485, and DS17885 (hereafter referred to as the DS17x85) provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed NV SRAM. Features ♦ Incorporates Industry-Standard DS12887 PC Clock Plus Enhanced Functions ♦ RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Through 2099 ♦ Optional +3.0V or +5.0V Operation ♦ SMI Recovery Stack ♦ 64-Bit Silicon Serial Number ♦ Power-Control Circuitry Supports System PowerOn from Date/Time Alarm or Key Closure ♦ Crystal Select Bit Allows Operation with 6pF or 12.5pF Crystal ♦ 12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode ♦ 114 Bytes of General-Purpose, Battery-Backed NV SRAM ♦ Extended Battery-Backed NV SRAM 2048 Bytes (DS17285/DS17287) 4096 Bytes (DS17485/DS17487) 8192 Bytes (DS17885/DS17887) ♦ RAM Clear Function ♦ Interrupt Output with Six Independently Maskable Interrupt Flags ♦ Time-of-Day Alarm Once per Second to Once per Day ♦ End of Clock Update Cycle Flag ♦ Programmable Square-Wave Output ♦ Automatic Power-Fail Detect and Switch Circuitry ♦ Available in PDIP, SO, or TSOP Package (DS17285, DS17485, DS17885) ♦ Optional Encapsulated DIP (EDIP) Package with Integrated Crystal and Battery (DS17287, DS17487, DS17887) ♦ Optional Industrial Temperature Range Available ♦ Underwriters Laboratory (UL) Recognized Applications Embedded Systems Utility Meters Security Systems Network Hubs, Bridges, and Routers
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