MM74HC181 Overview
Description
These arithmetic logic units (ALU) function generators utilize advanced silicon-gate CMOS technology They possess the high noise immunity and low power consumption of standard CMOS integrated circuits as well as the ability to drive 10 LS-TTL loads The MM54HC181 MM74HC181 are arithmetic logic unit (ALU) function generators that have a complexity of 75 equivalent gates on a monolithic chip These circuits perform 16 binary arithmetic operations on two 4-bit words as shown in Tables 1 and 2 These operations are selected by the four function-select lines (S0 S1 S2 S3) and include addition subtraction decrement and straight transfer When performing arithmetic manipulations the internal carries must be enabled by applying a low-level voltage to the mode control input (M) A full carry look-ahead scheme is made available in these devices for fast simultaneous carry generation by means of two cascade-outputs (pins 15 and 17) for the four bits in the package When used in conjunction with the MM54HC182 or MM74HC182 full carry lookahead circuits high-speed arithmetic operations can be performed The method of cascading HC182 circuits with these ALU’s to provide multi-level full carry look-ahead is illustrated under typical applications data for the MM54HC182 MM74HC182 If high speed is not of importance a ripple-carry input (Cn) and a ripple-carry output (Cn a 4) are available However the ripple-carry delay has also been minimized so that arithmetic manipulations for small word lengths can be performed without external circuitry.
