SNVS783K January 2012 – August 2021 LM5017
The on-time for the LM5017 device is determined by the RON resistor and is inversely proportional to the input voltage (VIN), resulting in a nearly constant frequency as VIN is varied over the operating range. The on-time for the LM5017 can be calculated using Equation 3.
See Figure 6-5. RON should be selected for a minimum on-time (at maximum VIN) greater than 100 ns for proper operation. This requirement limits the maximum switching frequency for high VIN.