AP6015

High Efficiency Step-Down Low Power DC-DC Converter

AP6015 Rev.

2

14 of 18

AUGUST 2008

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Application Information

(Continued)

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

×

−

×

=

Δ

)

(

1

2

)

(

)

(

L

MAX

O

MAX

L

I

I

I

Δ

+

=

Where:

f= Switching frequency (1MHz typical)

L = Inductor value

Vcc=3.6V

Vout=2.5V

f=1MHz

L=3.3uH

Vcc=3.6V

Vout=2.5V

f=1MHz

L=1.8uH