NCN9252MUGEVB
http://onsemi.com
4
PCB LAYOUT GUIDELINES
Electrical Layout Considerations
Implementing a high speed USB device requires paying
attention on USB lines and traces to preserve signal
integrity. The demonstration board serves as a layout
example and can support the design engineers to preserve
high speed performances.
Electrical layout guidelines are:
•
The bypass capacitor must be placed as close as
possible to the V
CC
input pin for noise immunity
.
•
The characteristic impedance of each High Speed USB
segment must be 45
W
.
•
The ground plane of the PCB will be used to determine
the characteristic impedance of each line.
•
All corresponding D+ / D
−
line segment pairs must be
the same length.
•
The use of vias to route these signals should be avoided
when possible
.
•
The use of turns or bends to route these signal should
be avoided when possible
.
EVALUATION BOARD PCB LAYOUT
Figure 4. Evaluation Board Layout. Top Layer: Magenta. Bottom Layer: Cyan.
