MM54HC181/MM74HC181Arithmetic Logic Units/Function GeneratorsGeneral Des criptionThese arithmetic logic units (ALU)/function generators utilizeadvanced silicon-gate CMOS technology. They possessthe high noise immunity and low power consumption ofstandard CMOS integrated circuits, as well as the ability todrive 10 LS-TTL loads.The MM54HC181/MM74HC181 are arithmetic logic unit(ALU)/function generators that have a complexity of 75equivalent gates on a monolithic chip. These circuits perform16 binary arithmetic operations on two 4-bit words asshown in Tables 1 and 2. These operations are selected bythe four function-select lines (S0, S1, S2, S3) and includeaddition, subtraction, decrement, and straight transfer.When performing arithmetic manipulations, the internal carriesmust be enabled by applying a low-level voltage to themode control input (M). A full carry look-ahead scheme ismade available in these devices for fast, simultaneous carrygeneration by means of two cascade-outputs (pins 15 and17) for the four bits in the package. When used in conjunctionwith the MM54HC182 or MM74HC182, full carry lookaheadcircuits, high-speed arithmetic operations can be performed.The method of cascading HC182 circuits with theseALU's to provide multi-level full carry look-ahead is illustratedunder typical applications data for the MM54HC182/MM74HC182.If high speed is not of importance, a ripple-carry input (Cn)and a ripple-carry output (Cna4) are available. However,the ripple-carry delay has also been minimized so that arithmeticmanipulations for small word lengths can be performedwithout external circuitry.FeaturesY Full look-ahead for high-speed operations onlong wordsY Arithmetic operating modes:AdditionSubtractionShift operand a one position magnitude comparisonPlus twelve other arithmetic operationsY Logic function modes:Exclusive-ORComparatorAND, NAND, OR, NORPlus ten other logic operationsY Wide operating voltage range: 2V±6VY Low input current: 1 mA maximumY Low quiescent current: 80 mA maximum