LM5145: What happens if the RT pin is left floating?

Here are some details:

PJC:  this is the resistor to the "RT" pin for the 4 volt converter control chip U8. If this resistor is opened, then the this pin has no connection and is left floating.   From the LM5145 U8 data sheet, "an RT pin resistor is required even when using the SYNCIN pin to synchronize to an external clock."  With this resistor opened, the control chip U8 would not have a defined frequency of operation.  Thus the chip U8 would not operate & so the 4 volt converter.  

I cannot find a direct statement that the chip won't work if the RT pin is floating, though...