LMR14020-Q1: Max Css for soft start

Hi Johnny,

The reason why we specify a max Css is because the output capacitors needs to be charged up within a certain amount of time. Capacitors are a great component during the steady state as the provide the output load with a steady supply of charge, but during startup there's a huge inrush current that's dedicated to charging them. If you ramp too slowly, the device will go into current limit trying to charge the output caps. This will cause the device to shut off, and try to start again after a few mS, only for it to go into current limit again.

For this device we decided that anything larger than 4.7nF will cause this phenomenon.

Thanks,
Andrew