Difficulty: Easy
Correct Answer: Incorrect
Explanation:
Introduction / Context: Two standard accuracy metrics for DACs (and ADCs) are differential nonlinearity (DNL) and integral nonlinearity (INL). Confusing these definitions is common. This question checks whether “linearity” is defined by step-size error, or whether that definition belongs to a different metric.Given Data / Assumptions:
Concept / Approach: DNL quantifies the deviation of each step size from 1 LSB. INL quantifies the deviation of the converter\u2019s actual transfer function from a straight reference line (often best-fit or end-point). Therefore, saying “linearity is measured by deviation of step size” is inaccurate; that specific deviation defines DNL, not overall linearity (INL).Step-by-Step Solution:
Define DNL: DNL[k] = (actual step[k] − ideal 1 LSB) / 1 LSB.Define INL: INL[k] = (actual code edge[k] − ideal straight-line edge[k]) / 1 LSB.Conclude: The statement confuses DNL (step error) with linearity (INL).Verification / Alternative check:
Check converter datasheets: specifications list both INL and DNL separately with distinct definitions and test methods.Why Other Options Are Wrong:
Correct: Would mislabel DNL as “linearity.”True only for PWM DACs: The DNL/INL definitions are universal, not PWM-specific.Depends only on reference voltage: Reference affects gain/offset but not the definitional distinction between INL and DNL.Common Pitfalls:
Using DNL and INL interchangeably in specifications.Ignoring whether INL is end-point or best-fit when comparing devices.Final Answer:
Incorrect
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