Difficulty: Easy
Correct Answer: Correct
Explanation:
Introduction / Context:The DAC0808 and its Motorola/ON counterpart MC1408 are classic 8-bit DACs widely used in education and industry. They are inexpensive, easy to interface, and represent the canonical example of a current-output DAC that requires an external I/V converter to produce a voltage output.
Given Data / Assumptions:
Concept / Approach:These devices sink/source a controlled output current proportional to the applied digital code and reference. Because they are current-output, applications commonly include an op-amp configured as a transimpedance amplifier to generate a voltage with desired polarity and scaling. Their popularity stems from availability, cost, and abundant example circuits in textbooks and application notes.
Step-by-Step Solution:
Identify device type: DAC0808/MC1408 are 8-bit current-output DACs.Note interface: parallel digital inputs, reference current, and Iout pins.Recognize external I/V conversion for voltage output.Verification / Alternative check:Typical specifications list full-scale current, compliance voltage, reference requirements, and settling times, confirming current-output behavior and 8-bit resolution.
Why Other Options Are Wrong:
“Incorrect”: Contradicts well-documented device characteristics.“Only with R-2R ladders”: They are themselves DAC ICs; external R-2R is not required.“Voltage-output parts”: False; voltage output requires an external op-amp.“Depends on temperature grade”: Temperature affects accuracy/drift, not the basic description.Common Pitfalls:Forgetting to include an I/V stage and compliance limits, leading to linearity issues.
Final Answer:Correct
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