MPM3515 foldback frequency during 2MHz external Sync mode operation

In my case MPM3515 work with 2MHz external synchronization
Vin can change from 12V up to 29V (Vout =1V !)
According to datasheet IC will work with foldback 1.1 MHz frequency if Vin higher than 21V
Question is - what occur with external synchronization during Vin more than 21V, do it stay synchronized with every second edge of external frequency or lost synchronization at all?
I can change synchronization frequency down to 1MHz in my design (if need)
Question is - how will degrade max output current of IC with 1MHz?
Thank you

Hi mikhaili,

Thanks for your question.
Yes, MPM3515 will have a frequency foldback of 1.1MHz when Vin >21V.
Since your Vin will be changing, I’d suggest setting the frequency to <=1.1Mhz in order to keep the synchronizing consistent.
We don’t have a plot showing how output current will degrade with a 1MHz frequency sync.
However, you might find the efficiency plot on page 1 of the EVB datasheet useful.