Specifications

Rev. 1.0 January 2012
www.aosmd.com
Page 14 of 14
AOZ197
8
PCB Layout Consideration
Correct layout practices are essential for a working
design that will meet expectations. It is recommended
to use 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 be filled and uninterrupted.
Single Point Connection: Connecting IC GND to Bottom Layer PWR GND