MP4462 – 3.5A, 4MHz, 36V STEP-DOWN CONVERTER

MP4462 Rev. 1.02

www.MonolithicPower.com

11

3/4/2013

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Table 2—Inductor Selection Guide

Part Number

Inductance (µH)

Max DCR (Ω) Current Rating (A)

Dimensions

L x W x H (mm

Wurth Electronics

7447789002

2.2

0.019

4

7.3x7.3x3.2

7447789003

3.3

0.024

3.42

7.3x7.3x3.2

7447789004

4.7

0.033

2.9

7.3x7.3x3.2

744066100

10

0.035

3.6

10x10x3.8

744771115

15

0.025

3.75

12x12x6

744771122

22

0.031

3.37

12x12x6

TDK

RLF7030T-2R2

2.2

0.012

5.4

7.3x6.8x3.2

RLF7030T-3R3

3.3

0.02

4.1

7.3x6.8x3.2

RLF7030T-4R7

4.7

0.031

3.4

7.3x6.8x3.2

SLF10145T-100

10

0.0364

3

10.1x10.1x4.5

SLF12565T-150M4R2

15

0.0237

4.2

12.5x12.5x6.5

SLF12565T-220M3R5

22

0.0316

3.5

12.5x12.5x6.5

Toko

FDV0630-2R2M

2.2

0.021

5.3

7.7x7x3

FDV0630-3R3M

3.3

0.031

4.3

7.7x7x3

FDV0630-4R7M

4.7

0.049

3.3

7.7x7x3

919AS-100M

10

0.0265

4.3

10.3x10.3x4.5

919AS-160M

16

0.0492

3.3

10.3x10.3x4.5

919AS-220M

22

0.0776

3

10.3x10.3x4.5

Output Rectifier Diode

The output rectifier diode supplies the current to

the inductor when the high-side switch is off. To

reduce losses due to the diode forward voltage

and recovery times, use a Schottky diode.

Choose a diode whose maximum reverse

voltage rating is greater than the maximum

input voltage, and whose current rating is

greater than the maximum load current. Table 3

lists

example

Schottky

diodes

and

manufacturers.

Table 3—Diode Selection Guide

Diodes

Voltage/

Current

Rating

Manufacturer

B340A-13-F

40V, 3A

Diodes Inc.

CMSH3-40MA

40V, 3A

Central Semi

Input Capacitor

The input current to the step-down converter is

discontinuous, therefore a capacitor is required to

supply the AC current to the step-down converter

while maintaining the DC input voltage. Use low

ESR capacitors for the best performance. Ceramic

capacitors are preferred, but tantalum or low-ESR

electrolytic capacitors may also suffice.

For simplification, choose the input capacitor

with RMS current rating greater than half of the

maximum load current.