Difficulty: Easy
Correct Answer: Totem-pole
Explanation:
Introduction / Context:TTL logic families employ characteristic internal structures. Inputs often use multiemitter transistors, and outputs typically employ a push-pull stage that can both source and sink current quickly. This arrangement improves switching speed and provides stronger drive for connected loads.
Given Data / Assumptions:
Concept / Approach:The TTL push-pull output stage is called a totem-pole because two transistors are stacked vertically between Vcc and ground. One acts as an active pull-up for logic HIGH; the other acts as an active pull-down for logic LOW. Internal diodes or timing networks reduce shoot-through by preventing both from strongly conducting simultaneously.
Step-by-Step Solution:
Identify push-pull nature → both sourcing and sinking possible.Name of the stacked arrangement → totem-pole output.Differentiate from “open-collector,” which lacks an active pull-up.Verification / Alternative check:Review typical 7400-series internal diagrams; they show the characteristic stacked transistors in the output stage and label it as totem-pole.
Why Other Options Are Wrong:
Common Pitfalls:Confusing input architecture (multiemitter) with output topology; conflating package types with internal circuits.
Final Answer:Totem-pole
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