DS1746/DS1746P Y2K-Compliant, N onvolatile Timekeeping RAMs FEATURES PIN CONFIGURATIONS Integrated NV SRAM, Real-Time Clock, TOP VIEW Crystal, Power-Fail Control Circuit, and N.C. V 1 32 CC Lithium Energy Source Maxim A16 31 A15 2 Clock Registers are Accessed Identically to DS1746 A14 3 30 N.C. the Static RAM. These Registers are Resident A12 4 29 WE A13 A7 5 28 in the Eight Top RAM Locations. A6 6 27 A8 Century Byte Register (i.e., Y2K Compliant) A5 A9 7 26 Totally Nonvolatile with Over 10 Years of A4 8 25 A11 Operation in the Absence of Power A3 OE 9 24 A10 A2 10 23 BCD-Coded Century, Year, Month, Date, A1 CE 11 22 Day, Hours, Minutes, and Seconds with 12 21 DQ7 A0 Automatic Leap Year Compensation Valid 13 20 DQ6 DQ0 Up to the Year 2100 DQ1 14 19 DQ5 Battery Voltage-Level Indicator Flag DQ2 15 18 DQ4 Power-Fail Write Protection Allows for 10% GND 16 17 DQ3 V Power Supply Tolerance CC Encapsulated DIP Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is Applied for the First Time DIP Module Only N.C. N.C. 1 34 Maxim A15 33 2 N.C. Standard JEDEC Byte-Wide 128k x 8 Static A16 3 32 A14 DS1746P 31 RST A13 RAM Pinout 4 V 30 CC 5 A12 PowerCap Module Board Only 6 29 A11 WE 28 A10 7 OE Surface Mountable Package for Direct 27 8 A9 CE 26 A8 9 DQ7 Connection to PowerCap Containing 25 A7 10 DQ6 24 11 A6 DQ5 Battery and Crystal 23 12 A5 DQ4 22 A4 13 Replaceable Battery (PowerCap) DQ3 21 14 A3 DQ2 Power-On Reset Output 20 A2 15 DQ1 19 16 A1 DQ0 GND Pin-for-Pin Compatible with Other Densities X1 V X2 BAT 18 17 A0 GND of DS174xP Timekeeping RAM Also Available in Industrial Temperature PowerCap Module Board (Uses DS9034PCX+ or DS9034I-PCX+ PowerCap) Range: -40C to +85C Underwriters Laboratories (UL) Recognized 19-5503 Rev 6/13 1 of 16 DS1746/DS1746P Y2K-Compliant, Nonvolatile Timekeeping RAMs PIN DESCRIPTION PIN NAME FUNCTION PDIP PowerCap 1, 30 1, 33, 34 N.C. No Connection 2 3 A16 3 32 A14 4 30 A12 5 25 A7 6 24 A6 7 23 A5 8 22 A4 9 21 A3 10 20 A2 Address Input 11 19 A1 12 18 A0 23 28 A10 25 29 A11 26 27 A9 27 26 A8 28 31 A13 31 2 A15 13 16 DQ0 14 15 DQ1 15 14 DQ2 17 13 DQ3 Data Input/Output 18 12 DQ4 19 11 DQ5 20 10 DQ6 21 9 DQ7 16 17 GND Ground 22 8 Active-Low Chip Enable Input CE 24 7 Active-Low Output Enable Input OE 29 6 WE Active-Low Write-Enable Input 32 5 V Power-Supply Input CC Active-Low Power-Fail Output, Open Drain. Requires a pullup resistor for 4 RST proper operation. Crystal Connection, V Battery Connection. UL recognized to ensure BAT X1, X2, against reverse charging when used with a lithium battery V BAT (www.maximintegrated.com/qa/info/ul/) 2 of 16