19-6076 Rev 11/11 DS1243Y 64K NV SRAM with Phantom Clock FEATURES PIN CONFIGURATION Real-Time Clock Keeps Track of Hundredths TOP VIEW of Seconds, Seconds, Minutes, Hours, Days, V 1 28 CC RST Date of the Month, Months, and Years 27 WE A12 2 DS1243Y 8K x 8 NV SRAM Directly Replaces 3 26 N.C. A7 4 25 A6 A8 Volatile Static RAM or EEPROM 5 24 A5 A9 Embedded Lithium Energy Cell Maintains 6 23 A4 A11 Calendar Operation and Retains RAM Data A3 7 22 OE 8 21 A10 A2 Watch Function is Transparent to RAM 9 20 A1 CE Operation A0 10 19 DQ7 11 18 DQ6 DQ0 Automatic Leap Year Compensation Valid 12 17 DQ1 DQ5 Up to 2100 13 16 DQ2 DQ4 Lithium Energy Source is Electrically 14 15 DQ3 GND Disconnected to Retain Freshness Until Encapsulated Package Power is Applied for the First Time (720-Mil Extended) Standard 28-Pin JEDEC Pinout Full 10% Operating Range Accuracy is Better than 1 Minute/Month at +25C Over 10 Years of Data Retention in the Absence of Power Available in 120ns Access Time Underwriters Laboratories (UL) Recognized (www.maxim-ic.com/qa/info/ul) ORDERING INFORMATION PART TEMP RANGE PIN-PACKAGE DS1243Y-120+ 0C to +70C 28 EDIP (0.720a) + Denotes a lead(Pb)-free/RoHS-compliant package. 1 of 14 DS1243Y PIN DESCRIPTION PIN NAME FUNCTION Active-Low Reset Input. This pin has an internal pullup resistor RST 1 connected to V . CC 2 A12 3 A7 4 A6 5 A5 6 A4 7 A3 8 A2 Address Inputs 9 A1 10 A0 23 A11 21 A10 24 A9 25 A8 11 DQ0 12 DQ1 13 DQ2 15 DQ3 Data In/Data Out 16 DQ4 17 DQ5 18 DQ6 19 DQ7 20 CE Active-Low Chip-Enable Input 22 OE Active-Low Output-Enable Input 26 N.C. No Connection 27 WE Active-Low Write-Enable Input 28 V Power-Supply Input CC 14 GND Ground DESCRIPTION The DS1243Y 64K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 8192 words by 8 bits) with a built-in real time clock. The DS1243Y has a self-contained lithium energy source and control circuitry, which constantly monitors V for an out-of-tolerance condition. When such a CC condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent corrupted data in both the memory and real time clock. The Phantom Clock provides timekeeping information including hundredths of seconds, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The Phantom Clock operates in either 24-hour or 12-hour format with an AM/PM indicator. 2 of 14