RT8206L RICHTEK [Richtek Technology Corporation], RT8206L Datasheet - Page 25

• Manufacturer Part Number: RT8206L
• Description: High Efficiency, Main Power Supply Controller for Notebook Computers
• Manufacturer: RICHTEK [Richtek Technology Corporation]

DS8206L/M-07 June 2012
P
WQFN-32L 5x5 package
The maximum power dissipation depends on operating
ambient temperature for fixed T
resistance θ
the designer to see the effect of rising ambient temperature
on the maximum power dissipation.
Layout Considerations
Layout is very important in high frequency switching
converter design. If the layout is designed improperly, the
PCB could radiate excessive noise and contribute to the
converter instability. The following guidelines must be
strictly followed for a proper layout of RT8206L/M.
Copyright
Figure 7. Derating Curve of Maximum Power Dissipation
D(MAX)
Connect an RC low-pass filter from PVCC to VCC. The
RC low-pass filter is composed of an external capacitor
and an internal 10Ω resistor. It is recommended to bypass
VCC to GND with a 1μF capacitor. Place the capacitor
close to the IC, within 12mm (0.5 inch) if possible.
Keep current limit setting network as close as possible
to the IC. Routing of the network should avoid coupling
to high-voltage switching node.
Connections from the drivers to the respective gate of
the high side or the low-side MOSFET should be as
short as possible to reduce stray inductance. Use
0.65mm (25 mils) or wider trace.
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
©
= (125°C − 25°C) / (36°C/W) = 2.778W for
2012 Richtek Technology Corporation. All rights reserved.
0
JA
. The derating curve in the Figure 7 allows
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Ambient Temperature (°C)
50
75
J(MAX)
Four-Layer PCB
and thermal
100
125
All sensitive analog traces and components such as
VOUTx, FBx, GND, ENx, PGOODx, ILIMx, VCC, and
TON should be placed away from high voltage switching
nodes such as PHASEx, LGATEx, UGATEx or BOOTx
nodes to avoid coupling. Use internal layer(s) as ground
plane(s) and shield the feedback trace from power traces
and components.
Gather ground terminal of VIN capacitor(s), VOUTx
capacitor(s), and source of low side MOSFETs as close
as possible. PCB trace of the PHASEx node, which
connects to source of high side MOSFET, drain of low
side MOSFET and high voltage side of the inductor,
should be as short and wide as possible.
is a registered trademark of Richtek Technology Corporation.
RT8206L/M
www.richtek.com
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