MC74F85

    The MC54/74F85 is a 4-Bit Magnitude Comparator which compares two 4-Bit words (A0 -A3 , B0 -B3 ), A3 , B3  being the most significant inputs.  Operation is not restricted to binary codes; the device will work with any monotonic code.Three Outputs are provided: "A greater than B"( 0_A>B ), "A less than B" ( 0_A <B ),"A equal to B"(0A=B)  Three Expander Inputs, I_A >I_B  , I_A <I_B  , I_A  = I_B , allow cascading without external gates.  For proper compare operation, the Expander Inputs of MC74F85 to the least significant position must be connected as follows: I_A<I_B= I_A > B = L, I_A = B= H.  For serial (ripple) expansion the 0_A  >B  , 0_A  < B  Outputs are connected respectively to the I_A > B and I_A = B inputs of the next most significant comparator, as shown in Figure 1.  Refer to applications section of data sheet for high speed method of comparing large words.