TPS54218: TPS54218 Start-Up Delay Time

So far as I can tell this has not been specifically characterized. It is dependent on several variables, some of which are application specific. At EN rising edge, there is some deglitch and delay before the IC sees itself as enabled. Then the band gap and other internal circuits must be initialized. At this point the SS capacitor will start to charge. Is the SS voltage increases above 0V, the error amplifier will begin to charge the COMP pin RC network. When the COMP pin voltage rises above the minimum clamp voltage, the device will begin to switch. Probably the largest variable here is the COMP pin charging time, which is very much application dependent.