In standard TTL logic families, match each parameter to its typical DC level: (A) VOH(min), (B) VIH(min), (C) VOL(max) — choose the correct mapping from the given voltage values.

Question

Solve this multiple-choice question and choose the correct option.

Curioustab · Accepted Answer

Introduction / Context:Digital logic families (such as classic TTL) specify input and output voltage thresholds to ensure reliable logic-level interpretation. This question asks you to associate three common DC parameters—VOH(min), VIH(min), and VOL(max)—with their typical voltage values in a 5 V TTL system. Understanding these limits helps diagnose interfacing issues and guarantees noise margins when connecting chips from possibly different subfamilies. Given Data / Assumptions: VOH(min): minimum guaranteed HIGH output voltage from a TTL gate. VIH(min): minimum input voltage that a TTL input recognizes as HIGH. VOL(max): maximum guaranteed LOW output voltage from a TTL gate. Typical TTL reference values: 2.4 V (VOH(min)), 2.0 V (VIH(min)), 0.4 V (VOL(max)), and often 0.8 V (VIL(max)) for context. Concept / Approach:The mapping is rooted in standard TTL logic levels. Outputs must drive loads with sufficient headroom above/below the receiving inputs’ thresholds. Therefore, VOH(min) should be higher than VIH(min) to create a positive noise margin; likewise VOL(max) must be lower than VIL(max). Step-by-Step Solution: Match VOH(min) → 2.4 V: This is the minimum a TTL output guarantees in the HIGH state under rated load → A-1.Match VIH(min) → 2.0 V: This is the smallest voltage that a TTL input will reliably treat as HIGH → B-4.Match VOL(max) → 0.4 V: This is the largest voltage a TTL output will reach in the LOW state under load → C-3. Verification / Alternative check:Noise margins (typical): high-side margin = VOH(min) – VIH(min) = 2.4 – 2.0 = 0.4 V; low-side margin = VIL(max) – VOL(max) = 0.8 – 0.4 = 0.4 V. Balanced 0.4 V margins align with canonical TTL datasheets, confirming the mapping. Why Other Options Are Wrong: A-1, B-3, C-4: Assigns VIH(min) = 0.4 V, which is far too low for HIGH recognition in TTL. A-5, B-4, C-3: Maps VOH(min) to 0.8 V, which would collapse the high-level noise margin. A-1, B-5, C-2: Maps VOL(max) to 1.5 V, not acceptable for a LOW level. Common Pitfalls: Confusing input thresholds (VIH/VIL) with output guarantees (VOH/VOL). Assuming CMOS (e.g., rail-to-rail 0–VCC) levels; TTL margins are asymmetric and smaller. Final Answer:A-1, B-4, C-3

In standard TTL logic families, match each parameter to its typical DC level: (A) VOH(min), (B) VIH(min), (C) VOL(max) — choose the correct mapping from the given voltage values.

Answer

Explanation