DS8409 Datasheet, PDF (10/11 Pages) Richtek Technology Corporation – Green Mode Buck Converter

RT8409
0.6
Two-Layer PCB
0.5
0.4
0.3
0.2
0.1
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 1. Derating Curve of Maximum Power Dissipation
Layout Consideration
For best performance of the RT8409, the following layout
guidelines should be strictly followed.
The hold up capacitor, C1, must be placed as close as
possible to the VCC pin.
 The compensation component C2 and R1, must be
placed as close as possible to the COMP pin.
The IC SOURCE pin are high frequency switching nodes.
The traces must be as wide and short as possible.
Keep the main traces with switching current as short
and wide as possible.
Place C_IN, L1, R2, C_OUT, and D5 as close to each other
as possible.
Place the capacitor C1 as close as
possible to the VCC pin
V_MAIN
R_START
C1
C_IN
R3
VCC
D8
R2B R2A
Place the compensation
Components C2 and R1 as
close as possible to the IC
Analog GND
C2 R1
Power GND
C3
R2
L1
Analog GND
D5
D7
V_OUT
R4
C_OUT
Power GND
Place the Diode D5 and the resistor R2 as
close as possible to the SOURCE pin
Figure 2. PCB Layout Guide
Narrow trace from main circuit
to the IC to avoid the switching
noise
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10
is a registered trademark of Richtek Technology Corporation.
DS8409-00 September 2016