DAC accuracy error bound at full-scale A DAC has a full-scale (maximum) output of 12 V and specified accuracy of 0.1%. What is the maximum absolute error allowed for any output voltage?
-
A12 V
-
B120 mV
-
C12 mV
-
D0 V
Answer
Correct Answer: 12 mV
Explanation
Introduction / Context:Converter accuracy is commonly expressed as a percentage of full-scale range. This specification bounds the worst-case deviation from the ideal transfer function across the entire output span.
Given Data / Assumptions:
- Full-scale output = 12 V.
- Accuracy = 0.1% of full-scale.
- Error bound applies to any code’s analog output.
Concept / Approach:Maximum absolute error = accuracy_percent * full_scale. Here that is 0.1% of 12 V.
Step-by-Step Solution:Convert percent → 0.1% = 0.001 (fraction).Multiply → 12 V * 0.001 = 0.012 V.Express in millivolts → 0.012 V = 12 mV.
Verification / Alternative check:Many DAC datasheets define total unadjusted error or accuracy as a percentage of full-scale; unit conversion confirms 12 mV.
Why Other Options Are Wrong:
- 12 V: Implies 100% error; nonsensical.
- 120 mV: Corresponds to 1% of 12 V, not 0.1%.
- 0 V: Real devices have nonzero tolerance.
Common Pitfalls:Confusing accuracy with resolution; a fine LSB does not guarantee small absolute error without calibration.
Final Answer:12 mV