DALLAS SEMICONDUCTOR CORP DALLAS Ee oO ey She See 39E D BM 2614130 0003731 T MMDAL DS12i1 TUh23-37 DS1211 Nonvolatile Controller x 8 Chip is ness De pe ee naiers . FEATURES * Converts full CMOS RAMs Into nonvolatile memories * Unconditionally write protects when V,, Is out of tolerance * Automatically switches to battery when power fall occurs * 3 to 8 decoder provides control for up to elght CMOS RAMs * Consumes less than 100 nA of battery current * Tests battery condition on power-up Provides for redundant batteries * Power fall signal can be used to Interrupt proc- essor on power fallure Optional 5% or 10% power fail detection * Optional 20-pin SOIC surface mount package ~ ORDERING INFORMATION: DS1211 20-Pin DIP DS1211S 20-Pin SOIC DESCRIPTION The DS1211 Nonvolatile Controller x 8 Chip Is a CMOS circuit which solves the application prob- lem of converting CMOS RAMs Into nonvolatile memories. Incoming power Is monitored for an out-of-tolerance condition. When such a condi- tlon Is detected, the chip enables are inhibited to accomplish write protection and the battery Is switched on to supply RAMs with uninterrupted power. Special circuitry uses a low-leakage CMOS process which affords precise voltage PIN DESCRIPTION . Yeatt 1 20F] Voor Veco[]2 18[} nate ToL []3 18] CE\ PFAG4. 176] ceo CENTS = 16 J cet CEN (]s = 18] ]ce2y Cf}7 = 140 cea, B(js = 130 }Ne ALj9 = 120] cea GND {iO st ces, 20-PIN DIP (300 MIL) 20-PIN SOIC (300 MIL) PIN NAMES (\ Denotes Condition Low) A, B, Address Inputs CE\ Chip Enabie Input CE0\ - CE7\ Chip Enable Outputs GND Ground Veary + Battery 1 Veare +Battery2 TOL Power Supply Tolerance Veer + 5V Supply eco RAM Supply PLFA Power Fail N.C. No Connection detection at extremely low battery consumption. By combining the DS1211 nonvolatile controller/ decoder chip and lithium batteries ten years of nonvolatiie RAM operation can be achieved for up to eight CMOS memories. See the data sheet for the DS1212 Nonvolatile Controller x 16 Chip for electrical specifications and operation. 611 082290 177