Decoupling and bypassing: Evaluate — “Power-supply decoupling uses a radio-frequency (RF) capacitor to shunt high-frequency noise and spikes to ground.”

Introduction / Context:
Power-supply decoupling (bypass) is essential in digital systems to maintain stable logic levels and suppress switching noise. Small-value, low-ESL capacitors close to IC power pins provide a low-impedance path for high-frequency currents, thereby reducing voltage spikes on the supply rails.

Given Data / Assumptions:

• Digital ICs draw transient currents at clock edges.
• Bypass capacitors present low impedance at high frequency.
• Placement close to IC power pins minimizes loop inductance.

Concept / Approach:
A ceramic RF bypass (e.g., 0.1 µF) from Vcc to ground shunts fast transients locally, maintaining a clean local supply. Larger bulk capacitors stabilize lower-frequency sag. Together they form a multi-decade impedance control strategy.

Step-by-Step Solution:

Verification / Alternative check:
Scope measurements show reduced supply ripple/spikes when decoupling is properly applied at each IC compared to an undeco upled board.

Why Other Options Are Wrong:

• Incorrect / linear-only / >100 MHz-only / tantalum-only: Bypass principles are universal. Value and dielectric type are design choices; ceramics handle HF well, tantalum handles bulk energy but is not mandatory for HF shunting.

Common Pitfalls:
Placing capacitors far from pins; using only bulk capacitance; ignoring ground return path and plane quality; overlooking ESR/ESL effects at target frequencies.

Final Answer:
Correct