What is the effect of Vout on output noise? Noise tends to increase with increasing VOUT as the error amplifies gains it up. How much input capacitance do I need? Should it be low ESR? If the output capacitor meets LDO requirements and the LDO still oscillates or drops too far during a transient, then increase the size of the input capacitor, and look at the ESR. If it is a higher ESR capacitor, then go to a lower ESR capacitor.