Logic family comparison — TTL vs. CMOS Identify one classic advantage that transistor–transistor logic (TTL) historically has over CMOS logic families.

Introduction / Context:
Different logic families (TTL, CMOS, ECL, etc.) offer trade-offs in speed, power, noise immunity, and robustness. Knowing their comparative advantages guides part selection for legacy designs and understanding historical choices in digital systems.

Given Data / Assumptions:

• TTL refers to bipolar transistor logic (e.g., 74xx).
• CMOS refers to complementary MOS logic (e.g., 74HC/74HCT/4000-series).
• We refer to classic baseline characteristics, not special high-speed subfamilies.

Concept / Approach:
Historically, standard TTL offered higher switching speed than early CMOS at comparable supply voltages, though consuming more power. Modern CMOS families have largely closed or exceeded this gap, but the canonical textbook advantage credited to TTL is speed relative to early CMOS generations.

Step-by-Step Reasoning:
Compare propagation delay: TTL typically shorter than early CMOS.Evaluate ESD: CMOS is generally more sensitive to ESD than TTL.Cost and availability vary by era and vendor; not inherent advantages.Therefore, “faster” is the classic advantage.

Verification / Alternative check:
Datasheets for legacy 74xx TTL versus 4000-series CMOS show notably lower propagation delays for TTL at 5 V with similar loads, consistent with this generalization.

Why Other Options Are Wrong:

• Less expensive / more widely available depend on market and time period, not intrinsic technology.
• “Not sensitive to electrostatic discharge” is incorrect; CMOS is the family known for ESD sensitivity; claiming TTL’s nonsensitivity as its chief advantage is misleading in the context of the classic TTL-CMOS comparison.

Common Pitfalls:

• Assuming today’s high-speed CMOS equals early CMOS; improvements do not change the classic comparison taught in fundamentals.
• Confusing noise margin (often better in CMOS) with speed (historically stronger for TTL).

Final Answer:
faster