Use Equation 33 to calculate the required buck inductance for each channel based on a 30% inductor ripple current at nominal input voltages.
Equation 33.
Select a standard inductor value of 0.68 µH for both channels. Use Equation 34 to calculate the peak inductor currents at maximum steady-state input voltage. Subharmonic oscillation occurs with a duty cycle greater than 50% for peak current-mode control. For design simplification, the LM5143-Q1 has an internal slope compensation ramp proportional to the switching frequency that is added to the current sense signal to damp any tendency toward subharmonic oscillation.
Equation 34.
Based on Equation 10, use Equation 35 to cross-check the inductance to set a slope compensation equal to the ideal one times the inductor current downslope.