Specifications

CY7C68053
Document # 001-06120 Rev *J Page 39 of 42
12. PCB Layout Recommendations
The following recommendations must be followed to ensure
reliable high performance operation.
■ At least a four-layer impedance controlled board is required to
maintain signal quality.
■ Specify impedance targets (ask your board vendor what they
can achieve).
■ To control impedance, maintain trace widths and trace spacing
to within specifications.
■ Minimize stubs to minimize reflected signals.
■ Connections between the USB connector shell and signal
ground must be done near the USB connector.
■ Bypass or flyback caps on VBus, near connector, are
recommended.
■ DPLUS and DMINUS trace lengths must be kept within 2 mm
of each other in length, with preferred length of 20 to 30 mm.
■ Maintain a solid ground plane under the DPLUS and DMINUS
traces. Do not allow the plane to be split under these traces.
■ It is preferable to have no vias placed on the DPLUS or
DMINUS trace routing.
■ Isolate the DPLUS and DMINUS traces from all other signal
traces by no less than 10 mm.
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