
AOZ1977
PCB Layout Consideration
Correct layout practices are essential for a working
design that will meet expectations. It is recommended to
use a two-layer board for the design. However, a single
layer board would be sufficient if basic layout rules are
followed. In any SMPS layout, external components
should be grouped into Power or IC control. From typical
application circuit, there are two GND symbols. The
striped one is for Power GND and the solid one is for
Signal/Control GND. Both symbols are connected to a
single point connection on the layout, All Power
connections should be as short and wide as possible in
order to reduce undesired parasitic inductance. The
output capacitors should be physically placed in the
current path between the SMPS and the load. Input
capacitors should be placed as close as possible to the
input side of the inductor. To prevent interference and
system noise, it is critical that the switch node connection
for boost switch, inductor, and output diode must be as
short and close as possible. A GND copper layer covers
the top layer to help shield the noise. For two-layer
board, it is essential that the GND plane under this
switching node should be filled and uninterrupted.
PWR GND
Connect PWR GND and
SGNL GND at 1 point
S SGNL GND
Single Point Connection Connecting PWR GND and Signal GND
Rev. 2.1 May 2012
www.aosmd.com
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