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Oscillation problem of LDO

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boranavi

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I have big problem with our LDO which can drive up to 300mA dual. I couldn't find out output oscillation on simulation, but it happened on silicon. anyone can give tips to work this out.
 

pfd001

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Maybe your phase margin is not enough. Because of process variation, the phase margin is changed in silicion. Try to change your load cap
 

leo_o2

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What's your LDO structure? Maybe you can paste it here, then others can help you to find parasite pole.
What's poles and zeroes location? How many gain stage?
 

elbadry

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If the non-dominant pole is the output pole, try to reduce the load capacitance to the LDO. If not possible, you can add a resistor in parallel to the load cap. Both solutions will degrade the refulator's performance
 

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