RT9205SLASHACS datasheet(14/16 Pages) RICHTEK

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RT9205/A

Preliminary

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DS9205/A-03 May 2003

MOSFETs and the load. Also locate the PWM

controller near by MOSFETs.

A multi-layer printed circuit board is recommended.

Fig.13 shows the connections of the critical

components in the converter. Note that the capacitors

CIN and COUT represent numerous physical

capacitors. Use a dedicated grounding plane and use

vias to ground all critical components to this layer.

Apply another solid layer as a power plane and cut

this plane into smaller islands of common voltage

levels. The power plane should support the input

power and output power nodes. Use copper filled

polygons on the top and bottom circuit layers for the

PHASE node, but it is not necessary to oversize this

particular island. Since the PHASE node is subjected

to very high dV/dt voltages, the stray capacitance

formed between these islands and the surrounding

circuitry will tend to couple switching noise. Use the

remaining printed circuit layers for small signal

routing. The PCB traces between the PWM controller

and the gate of MOSFET and also the traces

connecting source of MOSFETs should be sized to

carry 2A peak currents.

Fig. 13

LOAD

RT9205/A

VCC

GND

LGATE

UGATE

VOUT

IQ1

IQ2

GND

RT9205/ACS Fiches technique(PDF) 14 Page - Richtek Technology Corporation