L1: The main parameter affected by the inductor is the output current ripple amplitude. The choice of inductor value therefore depends on both the minimum and maximum load currents, keeping in mind that the maximum ripple current occurs at maximum V_IN.

1. Minimum load current: To maintain continuous conduction at minimum I_O (100 mA), the ripple amplitude (I_OR) must be less than 200 mA peak-to-peak so the lower peak of the waveform does not reach zero. L1 is calculated using Equation 7:
   Equation 7.

   At V_IN = 90 V, L1 (min) calculates to 132 µH. The next larger standard value (150 µH) is chosen and, with this value, I_OR calculates to 176 mA peak-to-peak at V_IN = 90 V and 33 mA peak-to-peak at V_IN = 12 V.

2. Maximum load current: At a load current of 150 mA, the peak of the ripple waveform must not reach the minimum value of the LM5009 current limit threshold (250 mA). Therefore, the ripple amplitude must be less than 200 mA peak-to-peak, which is already satisfied in Equation 7. With L1 = 150 µH, at maximum V_IN and I_O, the peak of the ripple is 238 mA. Although L1 must carry this peak current without saturating or exceeding its temperature rating, L1 must also be capable of carrying the maximum value of the LM5009 current limit threshold (370 mA) without saturating because the current limit is reached during startup.