Inside the ADC0808 Which functional blocks are integrated on a typical ADC0808 IC?
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AA multiplexer
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BAn ADC
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CA 3-bit select input code
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DAll of the above
Answer
Correct Answer: All of the above
Explanation
Introduction / Context:The ADC0808 is a classic 8-bit successive-approximation ADC that simplifies multi-channel data acquisition by integrating selection logic and the converter core in one package. Recognizing its internal blocks helps with pinout understanding and system integration.
Given Data / Assumptions:
- ADC0808 provides multiple analog input channels.
- It uses internal addressing (select lines) to choose the active channel.
- It includes the SAR ADC engine.
Concept / Approach:
The ADC0808 integrates: (1) an 8-channel analog multiplexer for inputs, (2) an 8-bit SAR ADC core, and (3) a 3-bit address (select) input to choose any one of the eight channels. Thus, all listed items are present in the device, enabling compact DAQ designs.
Step-by-Step Solution:
Confirm presence of a multiplexer → yes, 8:1 analog MUX.Confirm presence of ADC → yes, 8-bit SAR.Confirm select input → yes, 3 address lines to select 1 of 8 channels.Therefore, “All of the above.”Verification / Alternative check:
Standard datasheets and training materials for the ADC0808/ADC0809 families clearly list these blocks and show the channel select truth table.
Why Other Options Are Wrong:
- Each individual block (A, B, C) is correct but incomplete; the device contains all of them.
Common Pitfalls:
- Forgetting that channel selection requires digital address lines; external decoders are not needed.
Final Answer:
All of the above