DS17285/DS17287/ Real-Time Clocks DS17485/DS17487/ DS17885/DS17887 General Description Features The DS17285, DS17485, DS17885, DS17287, DS17487, Incorporates Industry-Standard DS12887 PC and DS17887 real-time clocks (RTCs) are designed to Clock Plus Enhanced Functions be successors to the industry-standard DS12885 and RTC Counts Seconds, Minutes, Hours, Day, Date, DS12887. The DS17285, DS17485, and DS17885 (here- Month, and Year with Leap Year Compensation after referred to as the DS17x85) provide a real-time Through 2099 clock/calendar, one time-of-day alarm, three maskable Optional +3.0V or +5.0V Operation interrupts with a common interrupt output, a program- SMI Recovery Stack mable square wave, and 114 bytes of battery-backed NV SRAM. The DS17x85 also incorporates a number 64-Bit Silicon Serial Number of enhanced functions including a silicon serial number, Power-Control Circuitry Supports System Power- power-on/off control circuitry, and 2k, 4k, or 8kbytes of On from Date/Time Alarm or Key Closure battery-backed NV SRAM. The DS17287, DS17487, and Crystal Select Bit Allows Operation with 6pF or DS17887 (hereafter referred to as the DS17x87) integrate 12.5pF Crystal a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS17x85 and DS17x87 12-Hour or 24-Hour Clock with AM and PM in power-control circuitry allows the system to be powered 12-Hour Mode on by an external stimulus such as a keyboard or by a 114 Bytes of General-Purpose, Battery-Backed NV time-and-date (wake-up) alarm. The PWR output pin is SRAM triggered by one or either of these events, and is used to Extended Battery-Backed NV SRAM turn on an external power supply. The PWR pin is under 2048 Bytes (DS17285/DS17287) software control, so that when a task is complete, the 4096 Bytes (DS17485/DS17487) system power can then be shut down. 8192 Bytes (DS17885/DS17887) For all devices, the date at the end of the month is auto- RAM Clear Function matically adjusted for months with fewer than 31 days, including correction for leap years. It also operates in Interrupt Output with Six Independently Maskable either 24-hour or 12-hour format with an AM/PM indicator. Interrupt Flags A precision temperature-compensated circuit monitors Time-of-Day Alarm Once per Second to Once per the status of V . If a primary power failure is detected, CC Day the device automatically switches to a backup supply. A End of Clock Update Cycle Flag lithium coin cell battery can be connected to the V BAT input pin on the DS17x85 to maintain time and date oper- Programmable Square-Wave Output ation when primary power is absent. The DS17x85 and Automatic Power-Fail Detect and Switch Circuitry DS17x87 include a V input used to power auxiliary BAUX Available in PDIP, SO, or TSOP Package functions such as PWR control. The device is accessed (DS17285, DS17485, DS17885) through a multiplexed byte-wide interface. Optional Encapsulated DIP (EDIP) Package with Applications Integrated Crystal and Battery (DS17287, DS17487, DS17887) Embedded Systems Utility Meters Optional Industrial Temperature Range Available Security Systems Underwriters Laboratory (UL) Recognized Network Hubs, Bridges, and Routers Ordering Information, Pin Configurations, and Typical Operating Circuit appear at end of data sheet. 19-5222 Rev 2 5/16DS17285/DS17287/ Real-Time Clocks DS17485/DS17487/ DS17885/DS17887 Absolute Maximum Ratings Voltage Range on V Pin Relative to Ground ...-0.3V to +6.0V Lead Temperature (soldering, 10s) .................................+260C CC Operating Temperature Range (Noncondensing) (Note: EDIP is hand or wave-soldered only.) Commercial.........................................................0C to +70C Soldering Temperature (reflow) .......................................+260C Industrial ......................................................... -40C to +85C Storage Temperature Range EDIP ............................................................... -40C to +85C PDIP, SO, TSOP ........................................... -55C to +125C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC Electrical Characteristics (V = +4.5V to +5.5V, or V = +2.7V to +3.7V, T = Over the operating temperature range, unless otherwise noted. Typical CC CC A values are with T = +25C, V = 5.0V or 3.0V and V = 3.0V, unless otherwise noted.) (Note 2) A CC BAT PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS (-5) 4.5 5.0 5.5 Supply Voltage (Note 3) V V CC (-3) 2.7 3.0 3.7 V Input Voltage V (Note 3) 2.5 3.0 3.7 V BAT BAT (-5) 2.5 3.0 5.2 V Input Voltage (Note 3) V V BAUX BAUX (-3) 3.7 V + CC (-5) 2.2 0.3 Input Logic 1 (Note 3) V V IH V + CC (-3) 2.0 0.3 (-5) -0.3 +0.8 Input Logic 0 (Note 3) V V IL (-3) -0.3 +0.6 (-5) 25 50 V Power-Supply Current CC I mA CC1 (Note 4) (-3) 15 30 (-5) 1.0 3.0 V Standby Current (Notes 4, 5) I mA CC CCS (-3) 0.5 2.0 Input Leakage I -1.0 +1.0 A IL I/O Leakage I (Note 6) -1.0 +1.0 A OL (-5), -1.0mA 2.4 Output Logic 1 Voltage (Note 3) V V OH (-3), -0.4mA 2.4 (-5), +2.1mA 0.4 Output Logic 0 Voltage V V OL AD0AD7, IRQ, SQW (Note 3) (-3), +0.8mA 0.4 (-5), +10mA 0.4 Output Logic 0 Voltage V V OL PWR (Note 3) (-3), +4mA 0.4 (-5) 4.25 4.37 4.5 Power-Fail Voltage (Note 3) V V PF (-3) 2.5 2.6 2.7 VRT Trip Point VRT (Note 3) 1.3 V TRIP Maxim Integrated 2 www.maximintegrated.com