Diodes AP6015 - Manual (Page 14)

AP6015
High Efficiency Step-Down Low Power DC-DC Converter
AP6015 Rev. 3 14 of 18 FEBRUARY 2009
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„
Inductor Selection
In order to avoid saturation of the inductor, the inductor should be rated at least for the maximum output
current plus the inductor ripple current which is calculated as:
f L
V
V
V I CC
O
O L Ч
−
Ч = Δ
) ( 1
2
) ( ) (
L
MAX O MAX L
I
I I
Δ
+ =
Where:
f= Switching frequency (1MHz typical)
L = Inductor value
△I
L
= Peak-to-peak inductor ripple current
I
L
(max) = Maximum inductor current
Vcc=3.6V Vout=2.5V f=1MHz L=3.3uH
Î△I
L
≒230mA
Vcc=3.6V Vout=2.5V f=1MHz L=1.8uH
Î△I
L
≒360mA
Application Information
(Continued)