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PCB Design question and answer
Last Updated : 2011/5/19

1, How to choose the PCB board?

Select PCB board must meet the design requirements and to the middle of production and cost balance point. Howto design PCB? Design requirements include two parts of electrical and institutions. Usually very high-speed PCB design board (greater than GHz frequencies), the problem of this material would be more important. For example, the now commonly used FR-4 material, the frequency of several GHz, the dielectric loss (dielectric loss) will greatly affect signal attenuation may not be combined. For electrical purposes, note that the dielectric constant (dielectric constant) and dielectric loss in the suitability of the designed frequency.

2, How to avoid high-frequency interference?

The basic idea to avoid high-frequency interference is to minimize the interference of high frequency electromagnetic signals, also known as crosstalk (Crosstalk). High-speed signals and can be used to widen the distance between the analog signal, or add ground guard / shunt traces in the analog signal next. Also note that the analog to the digital ground noise.

3, How to solve the signal integrity problem?

Signal integrity is basically impedance matching problem. Factors affecting the signal source impedance matching structure and the output impedance (output impedance), take the line characteristic impedance, load characteristics, routing topology (topology) structure and so on. Solution to this is by termination (termination) and adjust the alignment of the topology.

4, Differential wiring is how to achieve it?

Differential pair routing has two points to note, first, the length of two lines as long as far as possible, and the other is a two-line spacing (this spacing determined by the differential impedance) should remain unchanged, that is, to remain parallel. PCB Printing Solution,There are two ways in parallel, one for the two lines go in the same routing layer (side-by-side), a walk in the bottom line for the two adjacent layers (over-under). General ago by side-by-side (side by side, shoulder to shoulder) way to achieve more.

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