Rainbow Electronics MAX8728 User Manual
Page 27
MAX8728
Low-Cost, Multiple-Output
Power Supply for LCD Monitors/TVs
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3) Place all feedback voltage-divider resistors as close
to their respective feedback pins as possible. The
divider’s center trace should be kept short. Placing
the resistors far away causes their FB traces to
become antennas that can pick up switching noise.
Care should be taken to avoid running any feedback
trace near LX1, LX2, DRVP, or DRVN.
4) Place the INL pin and REF pin bypass capacitors as
close to the device as possible. The ground connec-
tion of the INL bypass capacitor should be connect-
ed directly to the GND pin with a wide trace.
5) Minimize the length and maximize the width of the
traces between the output capacitors and the load
for best transient responses.
6) Minimize the size of the LX1 and LX2 nodes while
keeping them wide and short. Keep the LX1 and LX2
nodes away from feedback nodes (FB1, FB2, FBP,
and FBN) and analog ground. Use DC traces as
shield if necessary.
Refer to the MAX8728 evaluation kit for an example of
proper board layout.
Chip Information
TRANSISTOR COUNT: 6752
PROCESS: BiCMOS