TPSM33615: Switching Frequency for Vin 18V

Hi Myles,

Please see equation 9 of the datasheet for an equation for picking your switching frequency.

2200kHz should work for your application, but table 7-1 in the datasheet notes that the recommended switching frequency for 12VOUT is 2000kHz instead.

Thank you,

Joshua Austria 

Equation 9 doesn't reference the output voltage, its just shows how to pick a frequency. The table doesn't show max output at 18vin so how do I know if there is enough headroom?

Hi Myles,

Apologies, I pointed you to the incorrect table. Table 7-6 in the datasheet gives the switching frequency ranges for the various output voltages that are achievable with a given input voltage range. As you are utilizing a VIN of 18V, we can estimate the correct columns to look at to be between 12VIN and 24VIN. Your best bet would be to use a 2200kHz switching frequency at 18VIN to get a 12VOUT at 1A max. Accounting for minimum off times and the inductor current ripple, I believe this should work.

However, as this is not tested, we will need to take it on the bench to do this evaluation. Would you like me to conduct these tests?

Thank you,
Joshua Austria

Joshua, 

Thanks, yes if you could test it that would be awesome!

Hi Myles,

Sounds good! I will test this and get back to you by the end of next week.

Thank you,

Joshua Austria