Question

Among logic families, which offers the highest speed (lowest propagation delay)?

• A. RTL
• B. TTL
• C. CMOS
• D. ECL

Hint:

Among common logic families, \[ \boxed{ \text{ECL is the fastest but has higher power consumption.} } \]

Answer 1

The Correct Option is D

Step 1: Recall the characteristics of logic families. Different logic families have different propagation delays. Emitter Coupled Logic (ECL) operates without transistor saturation, making it the fastest logic family.

Step 2: Choose the fastest logic family. Since ECL has the lowest propagation delay, \[ \boxed{\text{ECL}} \] offers the highest operating speed. Therefore, \[ \boxed{(D)} \] is the correct answer.