Hi all, I'm trying to build this USB2.0 board with a cypress CY7C68013A in TQFP128 package. According to the datasheet, I have to use at least a four-layer board to ensure the performance. And then it gives several pieces of recommendations on how to handle this four-layer board.
The problem is, this USB2.0 stuff is the only thing that requires extremely high EMC standard, and that I don't think I will waste the whole board for this minor area. I want to use a two-layer board, and I don't expect too much quality loss, is it possible?
Here are the recommendations from the datasheet:
The following recommendations should be followed to ensure
reliable high-performance operation.
• At least a four-layer impedance controlled boards are 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.
• Minimize stubs to minimize reflected signals.
• Connections between the USB connector shell and signal
ground must be done near the USB connector.
• Bypass/flyback caps on VBus, near connector, are recommended.
• DPLUS and DMINUS trace lengths should be kept to within
2 mm of each other in length, with preferred length of
20–30 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 preferred is 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.
If I use a two-layer board, will it be as simple as following EVERY BUT the first instruction? Thanks for your time.