Question

The figure of merit of a logic family is given by

• A. (fan out)(noise margin)
• B. (propagation delay time)/(power dissipation)
• C. (fan out)(propagation delay time)
• D. (noise margin)/(power dissipation)

Hint:

Logic efficiency = speed vs power trade-off.

Answer 1

The Correct Option is B

Concept: Figure of merit of logic families measures efficiency combining speed and power.

Step 1: Important parameters Two main parameters:

• Propagation delay (speed)

• Power dissipation

Step 2: Trade-off High speed → more power, low power → slower speed.

Step 3: Figure of merit definition \[ \text{Figure of merit} = \text{Power dissipation} \times \text{Propagation delay} \]

Step 4: Given options Equivalent form: \[ \frac{\text{Propagation delay}}{\text{Power dissipation}} \]

Step 5: Conclusion \[ \boxed{\frac{\text{Propagation delay}}{\text{Power dissipation}}} \]

Final Answer: \[ \boxed{(B)} \]