Input-level abbreviations in logic families: The standard abbreviation for the required HIGH input voltage level is VIH. Assess the correctness of this notation.
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ACorrect
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BIncorrect
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CCorrect only for ECL
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DCorrect only for CMOS, not TTL
Answer
Correct Answer: Correct
Explanation
Introduction / Context:Datasheets use standardized abbreviations to define logic thresholds and drive levels. Recognizing these acronyms is essential for interfacing different logic families safely and for computing noise margins.
Given Data / Assumptions:
- VIH denotes the minimum input voltage guaranteed to be recognized as a logic HIGH.
- VIL denotes the maximum input voltage guaranteed to be recognized as a logic LOW.
- VOH and VOL are the guaranteed output HIGH and LOW levels at specified load currents.
Concept / Approach:These four parameters—VIH, VIL, VOH, VOL—form the basis of noise margin calculations. Identifying VIH correctly ensures that the driving stage’s VOH meets or exceeds the receiving stage’s VIH under worst-case conditions.
Step-by-Step Solution:
Identify the abbreviation in question: VIH.Match definition: VIH = minimum HIGH input threshold.Cross-reference with common datasheets: TTL, CMOS, and LVC families all use VIH/VIL.Conclude the statement is correct.Verification / Alternative check:Any standard logic family datasheet glossary confirms the VIH/VIL conventions alongside VOH/VOL.
Why Other Options Are Wrong:
Incorrect: Conflicts with universal datasheet notation.Correct only for ECL or only for CMOS: The notation is widely used across families.Common Pitfalls:Confusing input thresholds with output levels; forgetting to include temperature and load conditions when checking compliance.
Final Answer:Correct