MP2456 – 0.5A, 50V, 1.2MHz, STEP-DOWN CONVERTER IN A TSOT23-6

MP2456 Rev. 1.01

www.MonolithicPower.com

12

1/24/2017

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PGND

C1

L1

D1

R1

R2

C2

SGND

1

2

Figure 2: PCB Layout

External Bootstrap Diode

An external bootstrap diode may enhance

regulator

efficiency

under

the

following

conditions:



VOUT=5V or 3.3V; and



High duty cycle: D=

IN

OUT

V

V

>65%

In these cases, add an external BST diode from

the output of the voltage regulator to the BST

pin, as shown in Figure 3.

MP2456

BST

External BST Diode

IN4148

5V or 3.3V

COUT

L

SW

Figure 3: Optional Bootstrap Diode for Enhanced

Efficiency

The recommended external BST diode is

IN4148, and the BST capacitor is 0.1µF-1µF.

Table 2: Inductor Selection Guide

Part Number

Inductance(uH)

Max DCR(

)

Current Rating(A)

Dimensions

L

WH(mm3)

Wurth

74408943047

4.7

0.05

2.2

4.8

4.83.8

74408942100

10

0.125

1.38

4.8

4.82.8

744775133

33

0.13

1.35

7.8

75

TDK

VLCF4028T-4R7N1R5-2

4.7

0.06

1.5

4

4.32.8

CLF5030NIT-100M-D

10

0.1

1.6

5

5.32.7

VLS5045EX-330M

33

0.24

1.3

5

54.5