C.

Select an inductor from the table of Figure 10 which

cross-references the inductor codes to the part numbers

of three different manufacturers. Complete specifica-

tions for these inductors are available from the respec-

tive manufacturers. The inductors listed in this table

have the following characteristics:

AIE: ferrite, pot-core inductors; Benefits of this type are

low electro-magnetic interference (EMI), small physical

size, and very low power dissipation (core loss). Be

careful not to operate these inductors too far beyond

their maximum ratings for E

•T and peak current, as this

will saturate the core.

Pulse: powdered iron, toroid core inductors; Benefits are

low EMI and ability to withstand E

•T and peak current

above rated value better than ferrite cores.

Renco: ferrite, bobbin-core inductors; Benefits are low

cost and best ability to withstand E

•T and peak current

above rated value. Be aware that these inductors gener-

ate more EMI than the other types, and this may inter-

fere with signals sensitive to noise.

DS011468-12

Note: These charts assume that the inductor ripple current inductor is approximately 20% to 30% of the average inductor current (when the regulator is under

full load). Greater ripple current causes higher peak switch currents and greater output ripple voltage; lower ripple current is achieved with larger-value

inductors. The factor of 20 to 30% is chosen as a convenient balance between the two extremes.

FIGURE 9. LM1577-ADJ/LM2577-ADJ Inductor Selection Graph

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