AAT2146W Datasheet, PDF (14/18 Pages) Skyworks Solutions Inc. – Low-Noise, Fast Transient 600mA Step-Down Converter

DATA SHEET
AAT2146W
Low-Noise, Fast Transient 600mA Step-Down Converter
Layout
The suggested PCB layout for the AAT2146W is shown in
Figures 2, 3, and 4. The following guidelines should be
used to help ensure a proper layout.
1. Connect the input capacitor (C2) as close as possible
to VIN (Pin 3) and PGND (Pins 6-8).
2. Connect C1 and L1 as close as possible to the device
pins. The connection of L1 to the LX pin should be as
short as possible.
3. Separate the feedback trace or OUT pin (Pin 2) from
any power trace and connect as close as possible to
the load point. Sensing along a high-current load
trace will degrade DC load regulation. If external
feedback resistors are used, place them as close as
possible to the OUT pin (Pin 2) to minimize the
length of the high impedance feedback trace.
4. Keep the resistance of the trace from the load return
to the PGND (Pins 6-8) 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.
A high density, small footprint layout can be achieved
using an inexpensive, miniature, non-shielded, high DCR
inductor. More care must be taken when laying out the
copper board. For example, a non-shielded inductor will
have a larger radiated magnetic field than a shielded
inductor. Comparatively, the feedback trace must be
placed further away from the non-shielded inductor.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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202008A • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • May 28, 2012