TPSM33615: Pin 11 Connection Question

Part Number: TPSM33615

Tool/software:

Hello team - 

On my CCA, I have the TPSM33615 “F” version installed to convert 28V to 5V. I have the MODE/SYNC pin 11 connected to VCC to generate Fs=1MHz because I thought I was using the RT version (“non-F” version). I’m ok with a fixed switching frequency of 1MHz. Is it ok to have the FRDNR version hooked up with VCC connected to Pin 11? I do notice the ENABLE/UVLO pin has quite a bit of noise/deviation at 1MHz even though it does turn on & off at my calculated values ( using R divider for UVLO). 

Thank you!