High-frequency PCB is advancing to the trend of high speed, low consumption, small volume, and high anti-interference ability, which demands many new requirements of the design of PCB.
The design of high-frequency PCB is an important stage of the electrical production design. After the electrical schematic diagram is finished, according to the structure demands, how many function boards should be adapted in accordance with the different functions, and the overall dimensions and the installment methods of each functional PCBs need to be decided, and also the convenience of debugging and maintenance, shielding, heat dissipation, EMI function, and other factors need to be considered at the same time.
Design Principles of High-Speed PCB Wiring:
Minimize the logic fan-out, and it's better to set only one load.
Avoid using through-hole between the output end and the receiving end of the high-frequency signal line, and avoid the cross of the pin pattern. Especially the clock signal line needs special consideration.
The two layers next to each other should be mutually perpendicular, and the elbow bend should be avoided.
When connecting the load resistor to the parallel end, connect as close as possible to the receiving end.
Use the cascade damping resistor when the open-circuit length is over the demanding value. Connect the resistor as close as possible to the pin of the output end when connecting that to the cascade end.
Ensure the artificial circuit and the digital circuit are separate. AGND and DGND must be connected by inductance or a magnetic bead, which should be connected as close as possible to the A/D transverter.
Ensure the full decoupling of the power.
Better to use surface-mounted resistance and capacitance.