AA18380
Agamem Microelectronics Inc.
PRELIMINARY
Switching Regulator Controller
■PC Board Layout Guideline
PCB layout is very important for DC-DC operation. Please follow the notes and sample layout below.
• Create a power ground island consisting of the input and output capacitor grounds and GND pins.
Connect all of these together with short, wide traces or a small ground plane and isolate the IC
ground from the power system.
• Make the lines in the high-current loop as wide as possible and placing the inductor, rectifier diode,
and output capacitors near the input capacitors and near the OUT and GND pins.
• Position the input filter capacitor C3 as close as possible to the VCC and ground pins, and assure
that there are no other paths for switching noise to enter the IC.
• Keep the length of the line between the OUT pin and the switching device (MOSFET or other
transistor) as short as possible to provide a clean switching pulse to the switching device.
• The inductor and rectifier diode need to be close with OUT pin.
• Place the feedback resistor – R2 as close to the IN1- pin as possible. The divider’s center trace
should be kept short. Placing the resistors far away causes picking up switching noise. Avoid running
the feedback trace near OUT pin.
• Minimize the length and maximize the width of the traces between the output capacitors and the load
for best transient responses. (Please refer to boost type application circuit for this PCB layout sample.)
■NOTES ON USE
• The information described herein is subject to change without notice.
• The specifications for the product described in this document are for reference only. Upon actual use,
therefore, please request that specifications to be separately delivered.
•The application circuit examples explain typical applications of the products, and do not guarantee the success
of any specific mass-production design.
• Application circuit diagrams and circuit constants contained herein are shown as examples of standard use
and operation. Please pay careful attention to the peripheral conditions when designing circuits and deciding
upon circuit constants in the set.
• Take account of common impedance when designing the earth line on a printed wiring board.
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©Copyright Agamem Microelectronics Inc.
www.agamem.com.tw
2007/1/15
AGAMEM [ AGAMEM MICROELECTRONIC INC. ]
