The switching frequency of the PFC converter can beset with an external resistor RFREQ at FREQ pin asshown Figure 2. The pin voltage at VFREQ is typical 1V.The corresponding capacitor for the oscillator isintegrated in the device and the RFREQ/frequency isgiven in Figure 4. The recommended operatingfrequency range is from 21kHz to 100kHz. As anexample, a RFREQ of 67kΩ at pin FREQ will set aswitching frequency FSW of 65kHz typically.