RT2808A

13

DS2808A-00 November 2012

www.richtek.com

©

Copyright 2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Layout Consideration

Follow the PCB layout guidelines for optimal performance

of the RT2808A.

Keep the traces of the main current paths as short and

wide as possible.

Put the input capacitor as close as possible to the device

pins (VIN and GND).

SW node is with high frequency voltage swing and should

be kept at small area. Keep analog components away

from the SW node to prevent stray capacitive noise pick-

up.

Connect feedback network behind the output capacitors.

Keep the loop area small. Place the feedback

components near the RT2808A.

Connect all analog grounds to a common node and then

connect the common node to the power ground behind

the output capacitors.

An example of PCB layout guide is shown in Figure 5

for reference.

Figure 3. Thermal Resistance vs. Copper Area Layout

Design

Figure 5. PCB Layout Guide

BOOT

NC

NC

FB

SW

VIN

EN

GND

GND

2

3

4

5

6

7

8

9

GND

R1

R2

SW

D1

The feedback components

should be connected as close

to the device as possible.

SW should be connected to inductor by

wide and short trace. Keep sensitive

components away from this trace.

L1

Input capacitor should be

placed as close to the IC

as possible.