Today, we will share 14 wiring tips for 4 layer PCB, hope those some help for you.1, Above 3 lines, try to make line loops through each point, so it easy to test, and wire length as short as possible.2, Don’t put the line between pins, particularly between the IC pins and surroundings.3, Between the different layers of lines not parallel as far as possible, so as to avoid forming capacitance.4, Wiring is straight as much as possible, or 45-degree line, to avoid electromagnetic radiation.5, Ground line, power line at least 10-15mil(for logic circuit).6, Between the line and the line as neat as possible.7, Component should be layout uniformity, convenient for assembly, soldering and so on. Legend layer should? in the current text layer, and put legends to right position to avoid being blocked and to ease of production.8, Consider more the layout of components, and SMD components with anode and cathode should be packaged and marked at last, avoid space conflict.9, Current wiring printed circuit boards can be used for 4-5mil, but usually 6mil LineWidth, 8mil space, 12/20mil pads. Wiring should be taken into account into the current impact.10, Function block elements together as much as possible, LCD components are not to close them.11, Through-hole should with solder mask (places -1 time).12, PAD and VIL size should be reasonably, and they should be not place under the battery.13, After wiring is complete, carefully check every on-line(including NETLABLE) are really connected.14, Oscillator circuit components close to the IC as possible, oscillation circuits as far as possible from the antenna and so on are subject to interference. Crystal Oscillator to be put under ground pads.