ISL78233 Datasheet, PDF (16/18 Pages) Intersil Corporation – 3A and 4A Compact Synchronous Buck Regulators

60
45
30
15
0
-15
-30
100
180
150
120
90
60
30
0
100
ISL78233, ISL78234
PCB Layout Recommendation
The PCB layout is a very important converter design step to make
sure the designed converter works well. For the ISL78233,
ISL78234 the power loop is composed of the output inductor L’s,
the output capacitor C_O, the PHASE pins, and the PGND pin. It is
necessary to make the power loop as small as possible and the
connecting traces among them should be direct, short and wide.
The switching node of the converter, the PHASE pins, and the
traces connected to the node are very noisy, so keep the voltage
feedback trace away from these noisy traces. The input capacitor
should be placed as close as possible to the VIN pin. The ground
of the input and output capacitors should be connected as close
as possible. The heat of the IC is mainly dissipated through the
1k
10k
100k
f (fi)
1M
thermal pad. Maximizing the copper area connected to the
thermal pad is preferable. In addition, a solid ground plane is
helpful for better EMI performance. It is recommended to add at
least 5 vias ground connection within the pad for the best
thermal relief.
1k
10k
100k
1M
f (fi)
FIGURE 37. SIMULATED LOOP GAIN
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FN8359.5
April 23, 2015