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