RT9203 RICHTEK [Richtek Technology Corporation], RT9203 Datasheet - Page 15

• Manufacturer Part Number: RT9203
• Description: Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT9203/A
Preliminary
A multi-layer printed circuit board is recommended. Figure
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.
IQ1
IL
V
OUT
5V
Q1
LOAD
IQ2
Q2
GND
VCC
GND
LGATE
RT9203/A
UGATE
FB
Figure 13
DS9203/A-10 March 2007
www.richtek.com
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