MP2403 – 3A, 32V, 250kHz INTEGRATED SYNCHRONOUS STEP-DOWN CONVERTER

MP2403 Rev.1.0

www.MonolithicPower.com

11

4/20/2010

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External Bootstrap Diode

An external bootstrap diode may enhance the

efficiency of the regulator, the applicable

conditions of external BST diode are:

Duty cycle is high: D=

IN

OUT

V

V

>65%

In these cases, an external BST diode is

recommended from the output of the voltage

regulator to BST pin, as shown in Fig.2

MP2403

SW

BST

C

L

BST

C

5V or 3.3V

OUT

External BST Diode

IN4148

Figure 2—Add Optional External Bootstrap

Diode to Enhance Efficiency

The recommended external BST diode is IN4148,

and the BST cap is 0.1~1µF.

TYPICAL APPLICATION CIRCUITS

INPUT

4.6V to 32V

OUTPUT

2.5V

3A

C3

4.7nF

C6

(optional)

D1

B340

(optional)

C5

10nF

MP2403

BS

IN

FB

SW

1

3

5

6

4

8

7

2

SS

GND

COMP

EN

Figure 3—MP2403 with AVX 47μF, 6.3V Ceramic Output Capacitor