Magnitude Comparator is a logical circuit, which compares two Signals A and B and generates three logical outputs, whether A > B, A = B, or A < B.
IC 7485 is a high speed 4-bit Magnitude, Comparator which compares two 4-bit words. The A = B Input must be held high for proper compare operation. These 4-bit magnitude comparators perform comparison of Straight binary or BCD codes. Three fully-decoded decisions about two, 4-bit words (A, B) are made and are externally available at three outputs. These devices are fully expandable to any number of bits without external gates. Words of greater Words of greater length may be compared by connecting Comparators in cascade.
The A > B, A < B, and A = B outputs of a stage handling less-significant bits are connected to the Corresponding inputs of the next stage handling more-significant bits. The stage handling the least significant bits must have a High-level voltage applied to the A = B input. The cascading path is Implemented with only a two-gate-level delay to reduce overall comparison times for long word.
