7485: 4-Bit Magnitude Comparator

This package compares two 4-bit words and provides an output indicating whether they are equal or which is larger.

Usually the input data words to be compared are weighted A1 = 1, A2 = 2, A3 = 4, and A4 = 8, while the second word is weighted B1 = 1, B2 = 2, B3 = 4, and B4 = 8.

If only 4-bit words are being compared, the A = B Cascade input should be wired high. The A > B and A < B Cascade inputs should be grounded.

If the two words are equal, the A = B goes high. If A > B, the A > B output goes high. If A < B, the A < B output goes high. Thus, a high state appears at the proper output; the other two remain low.

To work with 8-bit words, the outputs of the first 4-bit comparison (least significant bits) are connected to the Cascade Inputs of the second stage. The final answer appears as the outputs of the most significant 4-bit comparator, with the proper output going high.

Pinout
Pin # Pin Assignment
1 Input B4
2 Cascade A < B
3 Cascade A = B
4 Cascade A > B
5 Output A < B
6 Output A = B
7 Output A > B
8 Ground
9 Input B1
10 Input A1
11 Input B2
12 Input A2
13 Input A3
14 Input B3
15 Input A4
16 Power (+5V)

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