RT8280 RICHTEK [Richtek Technology Corporation], RT8280 Datasheet - Page 14

• Manufacturer Part Number: RT8280
• Description: 3A, 24V, 3MHz Step-Down Converter
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT8280
Layout Consideration
Follow the PCB layout guidelines for optimum performance
of the RT8280.
Copyright
www.richtek.com
14
SW node experiences high frequency voltage swing and
wide as possible.
device pins (VIN and GND).
should be kept in a small area. Keep analog components
away from the SW node to prevent stray capacitive noise
pick up.
Keep the traces of the main current paths as short and
Place the input capacitor as close as possible to the
©
2012 Richtek Technology Corporation. All rights reserved.
Input capacitor must
be placed as close
to the IC as possible.
GND
V
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
OUT
C
Figure 8. Derating Curves for RT8280 Package
OUT
0
C
C
IN
S
V
L
Figure 9. PCB Layout Guide
SW should be connected to inductor by
wide and short trace. Keep sensitive
components away from this trace.
IN
25
D
R
S
Ambient Temperature (°C)
SW
BOOT
GND
VIN
SW
50
GND
capacitors. Keep the loop area small. Place the feedback
components near the RT8280.
Connect all analog grounds to a common node and then
connect the common node to ground behind the output
capacitors.
An example of the PCB layout guide is shown in Figure
9 for reference.
2
3
4
Connect the feedback network behind the output
75
GND
is a registered trademark of Richtek Technology Corporation.
Four Layer PCB
9
Copper Area
70mm
50mm
30mm
10mm
8
7
6
5
Min.Layout
100
The feedback components
must be connected as close
to the device as possible.
2
2
2
2
EN
COMP
FB
RT
125
R2
R
R1
RT
V
OUT
C
C
C
P
GND
DS8280-02 March 2012
R
C