SNVSBK9C November 2019 – September 2020 LM63635-Q1
The switching frequency is set by the condition of the RT input. The condition of this input is tested when the device is first enabled. Once the converter is running, the switching frequency selection is fixed and cannot be changed until the next power-on cycle. Table 8-3 shows the selection programming. In the adjustable frequency mode, the switching frequency can be set between 250 kHz and 2200 kHz by proper selection of the value of RT. The curve in Figure 8-1 indicates the required resistor value for RT to set a desired switching frequency. It is not recommended that this input be allowed to float; the switching action ceases with no generated output voltage under this condition.
|RT INPUT||SWITCHING FREQUENCY|
|RT to AGND||Adjustable according to RT value|
|Float (not recommended)||No switching|