TPS92643-Q1: Led driver IC (What to know its best Switching Frequency)

Hello Shashikumar,

The answer is it depends on your design goals.  If you want a smaller solution then maybe you want to operate at 2.2MHz.  If you want a higher efficiency solution then operating around 300-450kHz might be a better solution.  You also have to consider if you will have to pass radiated and conducted emissions and what bands you want to stay away from based on that standard.  In your application you show you that Vin min is 10.5V and your output voltage is 10.1V.  That gives you no overhead and you will likely run into a drop out condition where the current will be less than you set it to.  Operating at lower frequencies would be better for this condition because you don't run into min off time problems.  We like to see an overhead of 3-5V generally speaking.  You could start at around 450kHz because that is below the AM band and it will give you better efficiencies and less likely to run into overhead issues.  The inductor will be a larger value and it likely means a larger physical size.  You should get the TPS92643EVM-204 and test out your design before doing a schematic and layout.  

-fhoude