SC251 datasheet(12/19 Pages) SEMTECH

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SC251

POWER MANAGEMENT

Applications Information (Cont.)

PCB Layout Considerations

Poor layout can degrade the performance of the DC-

DC converter and can be a contributory factor in EMI

problems, ground bounce and resistive voltage losses.

Poor regulation and instability can result.

A few simple design rules can be implemented to ensure

good layout:

Place the inductor and ﬁlter capacitors as close to the

device as possible and use short wide traces between

the power components.

Route the output voltage feedback and V

DAC path away

from the inductor and LX node to minimize noise and

magnetic interference.

Maximize ground metal on component side to improve

the return connection and thermal dissipation.

Separation between the LX node and GND should be

maintained to avoid coupling of switching noise to the

ground plane.

To further reduce noise interference on sensitive

circuit nodes, use a ground plane with several vias

connecting to the component side ground.

PGND

VIN

LOUT

COUT

PGND

CIN

SC251

VOUT

VREF

VMODE

VDAC

CREF

SC251 Datasheet(PDF) 12 Page - Semtech Corporation