SC3203 datasheet(17/20 Pages) SEMTECH

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SC3203

PCB Layout Guidelines

The optimum layout for the SC3203 is shown in Figure 12.

This layout shows an integrated mosfet buck regulator

with a maximum current of 3A. The total PCB area is

approximately 19.1mm x 11.3mm.

The VIN capacitor should be located immediately

next to the VIN and PGND pins, and mounted on

the same side of the pcb. Use wide traces or

copper areas to connect between the capacitor

and the IC pins.

Place the inductor near the LX pin and route

directly to the pin using wide, short traces.

A 1μF BYP capacitor should be located at and

directly connected to the BYP and AGND pins,

and mounted on the same side of the pcb.

A 0.01 μF Boost capacitor should be located at

and directly connected to the BST and LX pins,

and mounted on the same side of the pcb.

Using the placement shown below, the power

Ground plane can be a solid area that directly

connects the ground points for CIN, COUT, the

PGND PAD, and AGND pin.

•

Figure 12 — PCB Layout

Connect the AGND pin directly to the PGND pad.

For the RBOT connection to ground, route this to

the AGND pin while avoiding the high-noise

current path between CIN, the PGND PAD, and

COUT.

The FB trace and FB components should not be

placed or routed near the high-noise switching

nodes (LX, BST, VIN). Do not route FB traces

under or near the inductor: magnetic fields from

the inductor can induce switching noise into the

FB signal and cause erratic operation.

•

EN trace, 2nd layer

PGOOD trace, 2nd layer

FB trace for VOUT sense

2nd layer

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