Speed comparison of logic families: Evaluate the statement: “Emitter-Coupled Logic (ECL) IC technology is faster than TTL.”

Introduction / Context:
Logic families balance speed, power, noise margins, and voltage swings differently. Emitter-Coupled Logic is renowned for high speed due to small voltage swings and transistors that do not saturate. This item checks whether you recognize ECL’s speed advantage over traditional TTL families.

Given Data / Assumptions:

• ECL avoids transistor saturation, reducing stored charge and enabling rapid switching.
• TTL uses saturated switching (with variants like Schottky TTL to reduce storage delay).
• We compare families in their typical operating regimes.

Concept / Approach:
ECL’s differential, constant-current topology produces fast transitions with low, fixed voltage swings, which directly translates to higher propagation speed and bandwidth. TTL families improved speed via Schottky clamping and advanced processes, but mainstream ECL remains faster in raw propagation delay, historically used in high-speed communications and clock distribution.

Step-by-Step Solution:

Verification / Alternative check:
Prop-delay specs for classic ECL (hundreds of picoseconds to a few nanoseconds) beat standard TTL and many Schottky TTL parts, confirming the statement.

Why Other Options Are Wrong:

Common Pitfalls:
Ignoring ECL’s higher power and negative supply requirements; faster does not mean universally preferable.

Final Answer:
Correct