The datasheet (SWCS049G) specifies a 330uF cap with ESR between 9 and 15 mΩ for the VDDCtrl SMPS filter, but it does not give equations nor means to adjust the circuit.
The datasheet rates the output capacity of this switcher at 6A, and dimensions all external components to support that.
I would like to take advantage of lesser consumption of my design and reduce the size and cost of the external components.
On my particular design, the typical consumption for the DCDC Ctrl will be 1.2A or less, with a max of 1.6A for the sake of allowing some margin.
This is almost 1/4 of the rated current of the design on the datasheet.
I would like to use smaller, cheaper ceramic capacitors instead of the "monster" SP-cap that the datasheet recommend.
Can you please let me know if I will have to modify the feedback loop compensation (is that C1?) characteristics - and if so, how - in order to use ceramic cap instead of the SP-Cap for CO(VDDCtrl)?
Also, how much capacitance will I need?
Since the converter is running at 3 MHz, 40uF should be good enough to support a bit over 2A with < 60mV ripple.
Can you please confirm?
Thank you,
Bruno