AAT2315_07 Datasheet, PDF (15/22 Pages) Advanced Analogic Technologies – Dual 600mA Step-Down Converter with Synchronization

PCB Layout
Use the following guidelines to insure a proper layout:
1. Due to the pin placement of V_IN for both convert-
ers, proper decoupling is not possible with just
one input capacitor. The input capacitors C3 and
C9 should connect as closely as possible to the
respective VIN and GND as shown in Figure 3.
2. Connect the output capacitor and inductor as
closely as possible. The connection of the inductor
to the LX pin should also be as short as possible.
AAT2513
Dual 600mA Step-Down
Converter with Synchronization
3. The feedback trace should be separate 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. Place the
external feedback resistors as close as possible
to the FB pin. This prevents noise from being
coupled into the high impedance feedback node.
4. Keep the resistance of the trace from the load
return to GND to a minimum. This minimizes any
error in DC regulation due to potential differ-
ences of the internal signal ground and the
power ground.
5. For good thermal coupling, PCB vias are
required from the pad for the QFN paddle to the
ground plane. The via diameter should be 0.3mm
to 0.33mm and positioned on a 1.2 mm grid.
2513.2007.04.1.1
15