19-5497 Rev 9/10 DS1554 256k, Nonvolatile, Y2K-Compliant Timekeeping RAM www.maxim-ic.com FEATURES PIN CONFIGURATIONS Integrated NV SRAM, Real-Time Clock TOP VIEW (RTC), Crystal, Power-Fail Control Circuit, and Lithium Energy Source RST 1 32 V CC N.C. 31 N.C. Maxim 2 Clock Registers are Accessed Identically to DS1554 A14 3 30 IRQ/FT the Static RAM These Registers Reside in A12 4 29 WE the 16 Top RAM Locations A7 5 28 A13 A6 6 27 A8 Century Byte Register (i.e., Y2K Compliant) A5 A9 7 26 A4 8 25 A11 Totally Nonvolatile with Over 10 Years of A3 OE 9 24 Operation in the Absence of Power A2 10 23 A10 CE A1 Precision Power-On Reset 11 22 12 21 A0 DQ7 Programmable Watchdog Timer and RTC 13 20 DQ0 DQ6 Alarm 14 19 DQ1 DQ5 BCD-Coded Year, Month, Date, Day, Hours, DQ2 15 18 DQ4 GND 16 17 DQ3 Minutes, and Seconds with Automatic Leap- Year Compensation Valid Up to the Year Encapsulated DIP 2100 Battery Voltage-Level Indicator Flag Power-Fail Write Protection Allows for 10% 34 N.C. IRQ/FT 1 Maxim 33 N.C. 2 V Power-Supply Tolerance N.C. CC 3 32 A14 N.C. DS1554 31 4 A13 RST Lithium Energy Source is Electrically 30 A12 V 5 CC A11 6 29 Disconnected to Retain Freshness Until WE 28 A10 7 OE 27 8 A9 Power is Applied for the First Time CE 9 26 A8 DQ7 25 A7 10 DQ6 Also Available in Industrial Temperature 24 11 A6 DQ5 23 12 A5 DQ4 Range: -40C to +85C 22 13 A4 DQ3 21 14 A3 DQ2 15 20 A2 DQ1 19 16 A1 DQ0 V X1 GND BAT X2 18 A0 17 GND PowerCap Module Board (Uses DS9034PCX PowerCap) Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata. 1 of 18 DS1554 256k, Nonvolatile, Y2K-Compliant Timekeeping RAM PIN DESCRIPTION A0A14 - Address Inputs DQ0DQ7 - Data Input/Outputs IRQ/FT - Interrupt, Frequency Test Output (Open Drain) RST - Power-On Reset Output (Open Drain) CE - Chip Enable OE - Output Enable WE - Write Enable V - Power-Supply Input CC GND - Ground N.C. - No Connection X1, X2 - Crystal Connection V - Battery Connection BAT ORDERING INFORMATION VOLTAGE PART TEMP RANGE PIN-PACKAGE TOP MARK** (V) DS1554-70+ 0C to +70C 5.0 32 EDIP (0.740a) DS1554+070 DS1554-70IND+ -40C to +85C 5.0 32 EDIP (0.740a) DS1554+070 IND DS1554P-70+ 0C to +70C 5.0 34 PowerCap* DS1554P+70 DS1554P-70IND+ -40C to +85C 5.0 34 PowerCap* DS1554P+70 IND DS1554W-120+ 0C to +70C 3.3 32 EDIP (0.740a) DS1554W+120 DS1554W-120IND+ -40C to +85C 3.3 32 EDIP (0.740a) DS1554W+120 IND DS1554WP-120+ 0C to +70C 3.3 34 PowerCap* DS1554WP+120 DS1554WP-120IND+ -40C to +85C 3.3 34 PowerCap* DS1554WP+120 IND +Denotes a lead(Pb)-free /RoHS-compliant package. *DS9034-PCX+ or DS9034I-PCX+ required (must be ordered separately). **The top mark will include a + on lead-free devices. An IND anywhere on the top mark indicates an industrial temperature grade device. 2 of 18