DS6550A Datasheet, PDF (15/16 Pages) Richtek Technology Corporation – Synchronous DC-DC Step-Down Controller with 5V LDO

RT6550A
Layout Considerations
Layout is very important in high frequency switching converter design. Improper PCB layout can radiate excessive noise
and contribute to the converter’s instability. Certain points must be considered before starting a layout with the RT6550A.
 Place the filter capacitor close to the IC, within 12mm (0.5 inch) if possible.
 Keep current limit setting network as close as possible to the IC. Routing of the network should avoid coupling to high-
voltage switching node.
 Connections from the drivers to the respective gate of the high-side or the low-side MOSFET should be as short as
possible to reduce stray inductance. Use 0.65mm (25 mils) or wider trace.
 All sensitive analog traces and components such as FB, PGOOD, and should be placed away from high voltage
switching nodes such as PHASE, LGATE, UGATE, or BOOT nodes to avoid coupling. Use internal layer(s) as ground
plane(s) and shield the feedback trace from power traces and components.
 Place ground terminal of VIN capacitor(s), V_OUT capacitor(s), and Source of low-side MOSFETs as close to each other
as possible. The PCB trace of PHASE node, which connects to Source of high-side MOSFET, Drain of low-side
MOSFET and high voltage side of the inductor, should be as short and wide as possible.
Copyright ©2016 Richtek Technology Corporation. All rights reserved.
DS6550A-00 September 2016
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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