Question

Which of the following logic families has the highest fan-out?

• A. TTL
• B. ECL
• C. NMOS
• D. CMOS

Hint:

CMOS → best fan-out due to high input impedance and low output resistance.

Answer 1

The Correct Option is D

Logic Family	Fan-out
TTL	Moderate
ECL	Low
NMOS	Low to Moderate
CMOS	High

Fan-out refers to the number of input gates that can be driven by a single output gate without exceeding output current limitations while maintaining logical levels. It is an important parameter that indicates how many other gates or inputs a gate can drive. 

Among the logic families, CMOS has the highest fan-out due to its high input impedance and low output current requirements. This makes CMOS circuits capable of driving a larger number of gate inputs compared to other families like TTL, ECL, or NMOS.

Thus, CMOS is the logic family with the highest fan-out.