SC251EVB SEMTECH [Semtech Corporation], SC251EVB Datasheet - Page 12

• Manufacturer Part Number: SC251EVB
• Description: Step-down DC-DC Converter with Bias LDO for WCDMA Amplifi ers
• Manufacturer: SEMTECH [Semtech Corporation]

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:
1.
Applications Information (Cont.)
POWER MANAGEMENT
© 2006 Semtech Corp.
Place the inductor and fi lter capacitors as close to the
device as possible and use short wide traces between
the power components.
VDAC
VMODE
VREF
GD
EN
V
PGND
IN
C
REF
SC251
C
OUT
C
IN
12
2.
3.
4.
Route the output voltage feedback and V
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.
LX
L
OUT
PGND
V
OUT
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