Question

Choose the fastest logic family among the following:

• A. Transistor–Transistor Logic
• B. Emitter–Coupled Logic
• C. CMOS Logic
• D. Resistor–Transistor Logic

Hint:

Speed ranking (typical): \textbf{ECL} > fast TTL > CMOS > RTL; ECL trades power for speed by avoiding saturation.

Answer 1

The Correct Option is B

ECL avoids transistor saturation by operating transistors in the active region using differential emitter–coupled pairs, yielding the shortest propagation delays among standard logic families. TTL/RTL are slower; CMOS prioritizes low power over maximum speed (except for specialized high-speed CMOS). Hence \fbox{(B)}.