RT8253A RICHTEK [Richtek Technology Corporation], RT8253A Datasheet - Page 14

• Manufacturer Part Number: RT8253A
• Description: 3A, 23V, 340kHz Synchronous Step-Down Converter
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT8253A
Layout Considerations
Layout is very important in high frequency switching
converter design. PCB could radiate excessive noise and
contribute to the converter instability with improper layout.
Certain points must be considered before starting a layout
using the RT8253A (Figure 8).
www.richtek.com
14
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).
C
OUT
Input capacitor must
be placed as close
to the IC as possible.
GND
V
OUT
C
C
IN
IN
C
V
OUT
C
IN
L
R
S
*
S
*
SW should be connected to inductor by
wide and short trace. Keep sensitive
components away from this trace.
BOOT
SW
GND
Figure 8. PCB Layout Guide
VIN
SW
2
3
4
GND
GND
9
8
7
6
5
SW node is with high frequency voltage swing and
should be kept at small area. Keep sensitive
components away from SW node to prevent stray
capacitive noise pick up.
Ensure all feedback network connections are short and
direct. Place the feedback network and compensation
components are close to the chip as possible.
The GND pin and Exposed Pad should be connected to
a strong ground plane for heat sinking and noise
protection.
An example of PCB layout guide is shown in Figure 8
for reference.
C
SS
EN
COMP
FB
S
The feedback components
must be connected as close
to the device as possible.
R2
V
R
IN
R1
EN
V
OUT
C
C
GND
C
P
R
C
DS8253A-02 March 2011