As per data sheet recommendations, the inductor value should initially be chosen to produce a peak to peak ripple current between 20% and 40% of the maximum operating output current. A 30% current ripple was chosen for the LM27402 evaluation board. The minimum inductance required is calculated by:

Equation 6.

An actual inductor is selected based on a trade-off between physical size, efficiency, and current carrying capability. A Vishay IHLP5050 0.68-µH inductor results in a peak to peak current ripple of 6.4 A and offers a balance between efficiency (2.34-mΩ DCR), size (12.9 mm × 13.2 mm), and saturation current rating (49-A I_SAT).