Other Parts Discussed in Thread: TLV62569, TLV62585,
I am confused about the output capacitor selection that is specified on pages 15 and 18 of the documentation. I am using equation 16 on page 15 with an inductor value of 56 uH, a delta I of 1.5 A, Vin= 5V, Vout= 3.3V, and a delta V of 0.05. This gives me an extremely large value of 1.5 mF. I was surprised by this because the recommended output capacitor values are between 47 uF and 100 uF. My delta I value comes form the text directly above equation 16, where it says "For a load step from zero output current to its maximum, the following equation can be used to calculate the output capacitance". My delta V is 0.05 because I need a very small output ripple.
I then looked at the examples given on page 18 of the documentation to get a better understanding of the component values. In figure 22, the inductor is 10 uH, the delta I is 2 A (because the max output voltage is 2 amps), Vin= 5V, Vout= 3.3V and the output capacitor is 47uF. Using these values I can calculate their delta V from the equation on page 15 and got 0.5V ripple output voltage. This seems extremely large for a 3.3V buck converter.
I would like to confirm that the delta I needed in equation 16 is the current ripple (NOT peak-to-peak) and that it's value is the maximum output current. I would also like to confirm that delta V is the desired output voltage ripple (NOT peak-to-peak). I am concerned because all the suggested output capacitors have far lower values than the 1.5 mF I calculated.
