PPMIC BU

www.belling.com.cn

BL3406B Rev 1.5

Belling Proprietary Information. Unauthorized Photocopy and Duplication Prohibited

10/2009

©2009 Belling All Rights Reserved

9

BL3406B

1.5 MHz, 800mA Synchronous Buck Converter

frequency. Ceramic capacitors with X5R or

X7R dielectrics are recommended due to

their low ESR and high ripple current. The













×

×

+

×

×

×

−

×

≤

∆

2

8

1

)

(

C

f

ESR

L

f

V

V

V

V

V

OSC

OSC

IN

OUT

IN

OUT

OUT

Layout Considerations

When laying out the printed circuit board, the

following checklist should be used to ensure

proper operation of the BL3406B. These

items

are

also

illustrated

graphically

in

Figures 5 and 6. Check the following in your

layout:

1. The power traces, consisting of the GND

should be kept short, direct and wide.

feedback resistors? The resistive divider

R1/R2 must be connected between the (+)

plate of Cout and ground.

closely

as

possible?

This

capacitor

provides the AC current to the internal

power MOSFETS.

4. Keep the switching node, SW, away from

close as possible.

Figure 3. BL3406B-ADJ Layout Circuit

Figure 4. BL3406B-1.8 Layout Circuit

Figure 5. BL3406B-ADJ Suggested Layout

Figure 6. BL3406B-1.8 Suggested Layout

Run

GND

SW

V

IN

V

FB

BL3406B-ADJ

4

1

2

3

5

L1

2.2 H

C3

10uF

C2

22pF

R2

200k

R1

100k

V

2.7V - 4.2V

C1

4.7uF

Run

GND

SW

V

IN

V

OUT

BL3406B-18

4

1

2

3

5

L1

2.2 H

C2

10uF

V

2.7V - 4.2V

C1

4.7uF