SLUSDW9A June 2020 – June 2020 TPS51215A
Smaller values of inductor have better transient performance but higher ripple and lower efficiency. Higher values have the opposite characteristics. It is common practice to limit the ripple current to 25% to 50% of the maximum current. In this example, use 25%:
IP-P = 30 A × 0.4 = 12 A
At fSW = 600 kHz with a 20-V input and a 1.8-V output:
For this application, a 0.22-µH, 1.15-mΩ inductor from Cyntec with part number CMLE063T-R22MS is used.