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3 Board Layout
3.1 Board Layout Recommendations
3.2 Board Layers
Board Layout
This chapter provides board layout recommendations as well as figures of the EVM board layers.
As for all switching power supplies, the layout is an important step in the design, especially at high peak
currents and high switching frequencies. If the layout is not carefully done, the regulator could show
stability problems as well as EMI problems. Therefore, use wide and short traces for the main current path
and for the power ground tracks. The input and output capacitor, as well as the inductor should be placed
as close as possible to the IC. Use a common ground node for power ground and a different one for
control ground to minimize the effects of ground noise. Connect these ground nodes at any place close to
one of the ground pins of the IC.
The feedback divider should be placed as close as possible to the control ground pin of the IC. To layout
the control ground, it is recommended to use short traces as well, separated from the power ground
traces. This avoids ground shift problems, which can be due to superimposition of power ground current
and control ground current.
Figure 3. Top Assembly Layer
SLVU207 – April 2007 TPS6120xEVM-179 5
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