rt9204 ETC-unknow, rt9204 Datasheet - Page 12

• Manufacturer Part Number: rt9204
• Description: Dual Regulator - Standard Buck Pwm Dc-dc And Linear Power Controller
• Manufacturer: ETC-unknow

RT9204
Preliminary
The power components and the PWM controller
IL
IQ1
should be placed firstly. Place the input capacitors,
especially the high-frequency ceramic decoupling
V
PHASE
OUT
5V
capacitors, close to the power switches. Place the
Q1
+
+
+
output inductor and output capacitors between the
IQ2
LOAD
MOSFETs and the load. Also locate the PWM
controller near by MOSFETs.
GND
A multi-layer printed circuit board is recommended.
VCC
GND
Fig.11
shows
the
connections
of
the
critical
UGATE
RT9204
components in the converter. Note that the capacitors
FB
CIN and COUT each of them represents numerous
physical capacitors. Use a dedicated grounding plane
and use vias to ground all critical components to this
Fig. 11
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 island 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.
www.richtek-ic.com.tw
DS9204-00 February 2002
12