Digital Electronics: Principles, Devices and Applications

158 Digital ElectronicsFigure 5.42Two-input EX-NOR in CMOS.For both these conditions there is a conduction path available from ground to output, which verifiesthat the circuit satisfies the logic expression. Also, according to the logic expression for the AND-OR-INVERT gate, the output should be in a logic ‘1’ state when both AB and CD equal logic ‘0’. Thisimplies that:1. Either A or B or both are in a logic ‘0’ state.2. Either C or D or both are in a logic ‘0’ state.