DS1643 - Maxim Integrated Products

DS1643 Nonvolatile Timekeeping RAMs

PDIP 1 2 3 4 5 6 7 8 9 10 21 23 24 25 11 12 13 15 16 17 18 19 20 22 26 27 28 — 14 — PIN PowerCap 1, 2, 3, 31–34 30 25 24 23 22 21 20 19 18 28 29 27 26 16 15 14 13 12 11 10 9 8 7 — 6 5 4 17 NAME N.C. A12 A7 A6 A5 A4 A3 A2 A1 A0 A10 A11 A9 A8 DQ0 DQ1 DQ2 DQ3 DQ4 DQ5 DQ6 DQ7 CE OE CE2 WE VCC PFO GND X1, X2, VBAT No Connection FUNCTION Address Inputs Data Inpu.

Features

 Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit and Lithium Energy Source
 Clock Registers are Accessed Identically to the Static RAM. These Registers Reside in the Eight Top RAM Locations.
 Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power
 Access Times of 85ns and 100ns
 BCD-Coded Year, Month, Date, Day, Hours, Minutes, and Seconds with Leap Year Compensation Valid Up to 2100
 Power-Fail Write Protection Allows for ±10% VCC Power Supply Tolerance
 Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is A.