DS12885/DS12887/DS12887A/DS12C887/DS12C887A 19-5213 Rev 4 4/10 Real-Time Clocks General Description Features The DS12885, DS12887, and DS12C887 real-time Drop-In Replacement for IBM AT Computer clocks (RTCs) are designed to be direct replacements Clock/Calendar for the DS1285 and DS1287. The devices provide a real-time clock/calendar, one time-of-day alarm, three RTC Counts Seconds, Minutes, Hours, Day, Date, maskable interrupts with a common interrupt output, a Month, and Year with Leap Year Compensation programmable square wave, and 114 bytes of battery- Through 2099 backed static RAM (113 bytes in the DS12C887 and DS12C887A). The DS12887 integrates a quartz crystal Binary or BCD Time Representation and lithium energy source into a 24-pin encapsulated 12-Hour or 24-Hour Clock with AM and PM in DIP package. The DS12C887 adds a century byte at 12-Hour Mode address 32h. For all devices, the date at the end of the month is automatically adjusted for months with fewer Daylight Saving Time Option than 31 days, including correction for leap years. The Selectable Intel or Motorola Bus Timing devices also operate in either 24-hour or 12-hour format with an AM/PM indicator. A precision Interfaced with Software as 128 RAM Locations temperature-compensated circuit monitors the status of V . If a primary power failure is detected, the device 14 Bytes of Clock and Control Registers CC automatically switches to a backup supply. A lithium 114 Bytes of General-Purpose, Battery-Backed coin-cell battery can be connected to the V input BAT RAM (113 Bytes in the DS12C887 and pin on the DS12885 to maintain time and date operation when primary power is absent. The device is accessed DS12C887A) through a multiplexed byte-wide interface, which sup- RAM Clear Function (DS12885, DS12887A, and ports both Intel and Motorola modes. DS12C887A) Applications Interrupt Output with Three Independently Embedded Systems Maskable Interrupt Flags Utility Meters Time-of-Day Alarm Once Per Second to Once Security Systems Per Day Network Hubs, Bridges, and Routers Periodic Rates from 122s to 500ms Typical Operating Circuit End-of-Clock Update Cycle Flag Programmable Square-Wave Output CRYSTAL V CC Automatic Power-Fail Detect and Switch Circuitry Optional 28-Pin PLCC Surface Mount Package or X1 X2 V CC 32-Pin TQFP (DS12885) AS RESET R/W RCLR Optional Encapsulated DIP (EDIP) Package with Integrated Crystal and Battery (DS12887, DS DS83C520 DS12887A, DS12C887, DS12C887A) DS12885 CS Optional Industrial Temperature Range Available AD(07) SQW Underwriters Laboratory (UL) Recognized IRQ V BAT MOT GND Pin Configurations and Ordering Information appear at end of data sheet. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.Real-Time Clocks 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 ................................................... (Note: EDIP is hand or wave-soldered only.) Commercial (noncondensing) .............................0C to +70C Soldering Temperature (reflow) Operating Temperature Range ................................................... PDIP, SO, PLCC............................................................+260C Industrial (noncondensing)...............................-40C to +85C TQFP .............................................................................+245C Storage Temperature Range EDIP..................................................................-40C to +85C PDIP, SO, PLCC, TQFP ..................................-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, T = over the operating range, unless otherwise noted.) (Note 2) CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V (Note 3) 4.5 5.5 V CC V Input Voltage V (Note 3) 2.5 4.0 V BAT BAT V + CC Input Logic 1 V (Note 3) 2.2 V IH 0.3 Input Logic 0 V (Note 3) -0.3 +0.8 V IL V Power-Supply Current I (Note 4) 15 mA CC CC1 V Standby Current I (Note 5) mA CC CCS Input Leakage I -1.0 +1.0 A IL I/O Leakage I (Note 6) -1.0 +1.0 A OL Input Current I (Note 7) -1.0 +500 A MOT Output at 2.4V I (Note 3) -1.0 mA OH Output at 0.4V I (Note 3) 4.0 mA OL Power-Fail Voltage V (Note 3) 4.0 4.25 4.5 V PF VRT Trip Point VRT 1.3 V TRIP 2 DS12885/DS12887/DS12887A/DS12C887/DS12C887A