AAT1236 Analogic Corporation, AAT1236 Datasheet - Page 21

• Manufacturer Part Number: AAT1236
• Manufacturer: Analogic Corporation

PCB Layout Guidelines
Boost converter performance can be adversely
affected by poor layout. Possible impact includes
high input and output voltage ripple, poor EMI per-
formance, and reduced operating efficiency. Every
attempt should be made to optimize the layout in
order to minimize parasitic PCB effects (stray
resistance, capacitance, and inductance) and EMI
coupling from the high frequency SW node. A sug-
gested PCB layout for the AAT1236 boost convert-
er is shown in Figures 10 and 11. The following
PCB layout guidelines should be considered:
1. Minimize the distance from Capacitor C1 and
1236.2007.01.1.0
C2’s negative terminals to the GND pins. This
is especially true with output capacitor C2,
which conducts high ripple current from the
output diode back to the GND pins.
Figure 10: AAT1236 Evaluation Board
Top Side Layout.
High Efficiency White LED Drivers
2. Minimize the distance between L1 to D1 and
3. Maintain a ground plane and connect to the IC
4. Consider additional PCB metal area on D1’s
5. Do not connect the exposed paddle (bottom of
Figure 11: AAT1236 Evaluation Board
switching pin SW; minimize the size of the PCB
area connected to the SW pin.
GND pin(s) as well as the GND connections of
C1 and C2.
cathode to maximize heatsinking capability.
This may be necessary when using a diode
with a high V
the die) to either AGND or GND because it is
connected internally to SW. Connect the
exposed paddle to the SW pin or leave floating.
for Backlight and Keypad
Bottom Side Layout.
F
and/or thermal resistance.
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