PCB Bring-Up & Debug — question 4 of 10
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You probe a 3.3V rail directly at the load decoupling capacitor with your scope in AC-coupled mode and measure 150mVpp of ripple at the switching regulator's frequency. This rail feeds a precision ADC whose datasheet requires ripple to stay below 1% of the nominal voltage. What percentage ripple are you actually seeing, and is this rail acceptable to use as-is for that ADC?
This one resolves to a number. Give the value in the field below and your reasoning in the box — the number is checked exactly, by arithmetic.