In the event that the supply current changes sharply because of a change in the operating mode of the load IC, the output voltage of the LDO regulator drops instantaneously. In this situation, the LDO regulator provides negative feedback to return VOUT to a normal level. However, an LDO regulator with slow response exhibits a long foldback recovery time. The load-side IC might malfunction if its input voltage drops below the lower limit.
The use of an LDO regulator with excellent load transient response helps reduce a drop in VOUT and recovery time and therefore prevent the IC malfunction.
The drop in VOUT can also be reduced by increasing the value of the output capacitor. In this case, however, care should be exercised as to the rise time, oscillation, and inrush current immediately after the turn-on of the LDO regulator.