S6AP111A28 datasheet(42/51 Pages) CYPRESS

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Document Number: 002-08491 Rev.*C

Page 42 of 51

S6AP111A28

12.3 Layout

Consider the following points in your layout.

Try to provide a ground plane on the IC mounting surface. Try not to pass the heavy current path through the ground of around IC.

Try to connect the switching system parts on the surface and avoid connecting via the through-hole as much as possible.

Provide through-holes close to GND pins for switching system parts, and connect them to the inner ground plane.

Pay particular attention to the loop composed of the input capacitor (C

VCC), switching FET, and flyback diode (SBD), and make the

current loop as small as possible.

Place the bootstrap capacitor (C

BOOT1, CBOOT2) as close as possible to the IC CBx and LXx pins.

A large electric current will instantaneously flow in the net of the DRVHx and DRVLx pins connected to the switching FET gate.

Make the wiring as short as possible and aim for a wire width of approximately 0.8 mm.

Place the bypass capacitors (C

VCC, CVB, CVREF) that connect to the VCC, VB, and VREF as close to the pins as possible.

In addition, connect the GND pin for the bypass capacitor to the inner ground plane through the nearest through-hole.

In order to provide the IC with more accurate feedback on the ripple voltage that is generated by the output capacitor ESR,

individually pull the feedback wires connected to the VOx pins of this IC from the closest possible output capacitor pins. The wires

connected to the VOx and FBx pins are sensitive to noise. Try to keep these wires as far away from switching system parts as

possible.

In addition, place the output voltage setting resistors that are connected to these wires as close to the IC as possible. Make the FB

pin wire as short as possible. In addition, for the inner layer right under the mounting location, provide a ground plane that has

minimal ripple and spike noises, or provide a power plane if possible.

S6AP111A28 Datasheet(PDF) 42 Page - Cypress Semiconductor