MPQ2451-5/33―36V, 2.2MHz, 0.6A, STEP-DOWN CONVERTER, AEC-Q100 QUALIFIED

MPQ2451-5/33 Rev 1.0

www.MonolithicPower.com

13

5/25/2016

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APPLICATION INFORMATION

COMPONENT SELECTION

Inductor

The inductor supplies constant current to the

output load while being driven by the switched

input voltage. A larger-value inductor will result

in less ripple current and lower output ripple

voltage. However, the larger-value inductor is

typically physically larger, has a higher series

resistance, or has a lower saturation current.

To determine the inductance, allow the peak-to-

peak ripple current in the inductor to be

approximately 30%

of the maximum load

current. Also, chose a peak inductor current

below the maximum switch current limit. The

inductance value can be calculated by:





















IN

OUT

L

S

OUT

V

V

1

ΔI

f

V

1

L

the peak-to-peak inductor ripple current.

Choose an inductor that will not saturate under

the maximum inductor peak current. The peak

inductor current can be calculated by:

























IN

OUT

S

OUT

LOAD

LP

V

V

1

1

L

f

2

V

I

I

Table 2 lists a number of suitable inductors

from various manufacturers. The choice of

which style inductor to use mainly depends on

the price vs. size requirements and any EMI

requirement.