|IC Number||IC Name|
|74LS85||4-Bit Magnitude comparators|
8-Bit Magnitude Comparator - Comparators with three output terminals and checks for three conditions i.e greater than or less than or equal to is magnitude comparator. The Comparator is another very useful combinational logic circuit used to compare the value of two binary digits.
A magnitude digital Comparator is a combinational circuit that compares two digital or binary numbers in order to find out whether one binary number is equal, less than or greater than the other binary number. We logically design a circuit for which we will have two inputs one for A and another for B and have three output terminals, one for A > B condition, one for A = B condition and one for A < B condition.
Digital Magnitude Comparators are made up from standard AND, NOR and NOT gates that compare the digital signals present at their input terminals and produce an output depending upon the condition of those inputs.
An 8-bit comparator compares the two 8-bit numbers by cascading of two 4-bit comparators. The circuit connection of this comparator is shown below in which the lower order comparator A<B, A=B, and A>B outputs are connected to the respective cascade inputs of the higher-order comparator.
For the lower order comparator, the A=B cascade input must be connected High, while the other two cascading inputs A, B must be connected to LOW. The outputs of the higher-order comparator become the outputs of this eight-bit comparator.