SNAS879 December 2024 LMR60420
PRODMIX
The LMR60420 uses soft-start to prevent output voltage overshoots and large inrush currents during start-up. The soft-start time is fixed internally at 6ms (typical). The LMR60420 device operates correctly even if there is a voltage present on the output before the device is enabled.
To start-up the LMR60420 and initiate the soft-start sequence, the voltage applied to the VIN and EN pins must exceed VINUVLO(R) and VEN-TH(R) respectively. After these conditions are met, the soft-start sequence initiates and the output voltage reaches the set-point in 6ms (typical).
Dropout occurs when the input voltage falls below the voltage level of the output voltage setpoint. During this condition, the output voltage tracks the input voltage. After the input voltage increases, the output voltage increases with the same slope as during soft start.