SC121 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SC121' PDF : 23 Pages View PDF
SC121
Applications Information (continued)
PCB Layout Considerations
Poor layout can degrade the performance of the DC-DC
converter and can contribute to EMI problems, ground
bounce, and resistive voltage losses. Poor regulation and
instability can result.
The following simple design rules can be implemented to
ensure good layout:
• Place the inductor and filter capacitors as close
to the device as possible and use short wide
traces between the power components.
• Route the output voltage feedback path away
from the inductor and LX node to minimize
noise and magnetic interference.
• Maximize ground metal on the component side
to improve the return connection and thermal
dissipation. Separation between the LX node
and GND should be maintained to avoid cou-
pling capacitance between the LX node and the
ground plane.
• Use a ground plane with several vias connecting
to the component side ground to further reduce
noise interference on sensitive circuit nodes.
A suggested layout is shown in Figure 4.
7.0mm
COUT
VOUT
LX
LX
OUT
GND SC121 FB
IN
EN
CFB R1
(2nd layer)
5.2mm
R2
CIN
VIN
GND
Figure 4 — Layout Drawing
20
Share Link: 
