Lower dc/dc-converter ripple by using optimum capacitor hookup

IN and ground pins of the IC.

Figure 2, the output-voltage ripple is

ΔV_OUT(P-P)=ESR_COUT×ΔI_COUT(P-P).

Figure 1, the peak-to-peak ripple current in the output capacitor is equal to the peak-to-peak ripple current in the inductor:

ΔI_COUT(P-P)=ΔI_L(P-P)=(V_IN×duty cycle)/(f_SW×L), where ΔI_COUT(P-P)=output ripple current, ΔI_L(P-P)=inductor ripple current, and f_SW=switching frequency.

Figure 2, the peak-to-peak ripple current in the output capacitor is much higher than the inductor's ripple current alone; it is almost equal to the inductor's ripple current plus the input capacitor's ripple current:

Figure 2.