TPS2492: Vgate source current and start-up

Hello,

I've been using the TPS2492EVM-003, and exploring the option of placing and extra RC over the gate to get a soft start (positions R11 and C4). R11 is 1k as is suggested in datasheet. In the user guide, they give an example how a 39nF capacitor results in a 24ms start-up time, or 0.62ms/nF. However, I measure that it's actually 1.63ms/nF (i.e 36ms for a 22nF cap, and 150ms approx for a 100nF cap). That suggests a gate sourcing current of 8.3uA, far below what is given on the datasheet. Is the datasheet wrong here?

I've added a scope picture of start-up on 28V (I've adapted UVLO and OV on the EVM) using the enable/disable switch. CH1= input voltage, CH2= output voltage, CH3= gate voltage, to show the slow risetime. In this measurement, 22nF was placed on C4.