Calculate the inductor Volt • microsecond constant E × T (V × μs), with Equation 4:
VSAT = internal switch saturation voltage = 1.16 V
VD = diode forward voltage drop = 0.5 V
Calculate the inductor Volt • microsecond constant
(E × T),
Use the E × T value from the previous formula and match it with the E × T number on the vertical axis of the Inductor Value Selection Guide shown in Figure 30.
E × T = 34.2 (V × μs)
On the horizontal axis, select the maximum load current.
ILOAD(max) = 3 A
Identify the inductance region intersected by the E × T value and the maximum load current value. Each region is identified by an inductance value and an inductor code (LXX). From the inductor value selection guide shown in Figure 30, the inductance region intersected by the 34 (V • μs) horizontal line and the 3-A vertical line is 47 μH, and the inductor code is L39.
Select an appropriate inductor from the manufacturers' part numbers listed in Table 1. From the table in Table 1, locate line L39, and select an inductor part number from the list of manufacturers part numbers.