MP2560 – 2.5A, 4MHz, 42V STEP-DOWN CONVERTER

MP2560 Rev. 1.2

www.MonolithicPower.com

11

1/25/2010

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Table 1—Inductor Selection Guide

Part Number

Inductance (µH)

Max DCR (Ω) Current Rating (A)

Dimensions

L x W x H (mm

Wurth Electronics

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-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

FDV0630-4R7M

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 2

lists

example

Schottky

diodes

and

manufacturers.

Table 2—Diode Selection Guide

Diodes

Voltage/

Current

Rating

Manufacturer

B380-13-F

80V, 3A

Diodes Inc.

B390

90V, 3A

Diodes Inc.

CMSH3-100MA

100V, 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.