PRODUCT DATASHEET
AAT2515
SystemPowerTM
Dual 600mA FastTransient High Frequency Buck Converter
3. The feedback trace should be separate from any
power trace and connect as closely as possible to the
PCB Layout
The following guidelines should be used to insure a
proper layout.
load point. Sensing along a high-current load trace
will degrade DC load regulation. If external feedback
resistors are used, they should be placed as closely
as possible to the FB pin. This prevents noise from
being coupled into the high impedance feedback
node.
1. Due to the pin placement of VIN for both converters,
proper decoupling is not possible with just one input
capacitor. The large input capacitor C3 should con-
nect as closely as possible to VIN and GND, as shown
in Figure 2. The additional input bypass capacitor C8
is necessary for proper high frequency decoupling of
the second converter.
2. The output capacitor and inductor should be con-
nected as closely as possible. The connection of the
inductor to the LX pin should also be as short as
possible.
4. The resistance of the trace from the load return to
GND should be kept to a minimum. This will help to
minimize any error in DC regulation due to differ-
ences in the potential of the internal signal ground
and the power ground.
5. For good thermal coupling, PCB vias are required
from the pad for the TDFN paddle to the ground
plane. The via diameter should be 0.3mm to 0.33mm
and positioned on a 1.2 mm grid.
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2515.2007.12.1.0
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