VLSI Multiple Choice Questions on “CMOS Logic Gates”.
1. In negative logic convention, the Boolean Logic [1] is equivalent to:
A. +VDD
B. 0 V
C. -VDD
D. None of the mentioned
Answer: B
Clarification: In negative logic convention, the Boolean Logic [1] is equivalent to 0 V and Logic ‘0’ is equivalent to +VDD.
2. In positive logic convention, the true state is represented as:
A. 1
B. 0
C. -1
D. -0
Answer: A
Clarification: In positive logic convention, the Boolean logic ‘1’ is known to be representing true state.
3. The CMOS gate circuit of NOT gate is:
A. vlsi-questions-answers-cmos-logic-gates-q3a”>
B. vlsi-questions-answers-cmos-logic-gates-q3b”>
C. vlsi-questions-answers-cmos-logic-gates-q3c”>
D. vlsi-questions-answers-cmos-logic-gates-q3d”>
Answer: D
Clarification: The CMOS logic circuit for NOT gate has a p-MOS as a pull up transistor and n-MOS as driver transistor which is represented accurately in the below figurevlsi-questions-answers-cmos-logic-gates-q3d”>
4. The truth table which accurately explains the operation of CMOS not gate is:
A. vlsi-questions-answers-cmos-logic-gates-q4a”>
B. vlsi-questions-answers-cmos-logic-gates-q4b”>
C. vlsi-questions-answers-cmos-logic-gates-q4c”>
D. vlsi-questions-answers-cmos-logic-gates-q4d”>
Answer: D
Clarification: The output of CMOS depends on the state of nMOS and pMOS transistor.The correct truth table is:vlsi-questions-answers-cmos-logic-gates-q4d”>