I have an application where I need to run an atmega32u4 with a range from 3.3 to 7 volts (Allowing for at-least 200ma). Since I need the clock to be 16 I'm a bit concerned the chip can not keep up when driven as low as 3.3. So I was thinking of a buck boost chip. Something like the TI TPS63061DSCR. Is a buck boost chip the best way to do this?