7). The serial number of components should be close to the components of the border to decorate, uniform size, direction and tidy, not with components, holes and overlap welding plate. Components or connector pins 1 said direction; Is the sign of the cathode should be clearly marked on the PCB, not allowed to be covered; power conversion components (such as DC/DC converter, linear transformation power supply and switching power supply) side should have enough heat dissipation space and installation space, with sufficient welding outer space, etc.
11.2.2 General principles of the components wiring
Design personnel in the process of Multilayer pcb wiring needs to follow the general principles are as follows.
1)Components printed line spacing of setting principles. Amount of space between different network constraints are produced by electric insulation, process and component size and other factors. Such as a pin spacing is 8 mil chip components, then the chip of the [Clearance Constraint] cannot be set to 10 mil, designers need to separate this chip set a 6 mil design rules. At the same time, the distance between set to take into account the manufacturer's production capacity.
In addition, the influence of components is an important factor in electrical insulation, if two components or network of potential difference is bigger, be considered for electrical insulation problems. In general environment, clearance safe voltage of 200 V/mm, or 5.08 V/mil. So when the same piece of circuit board when there are both high voltage circuit and low voltage circuit, you need to pay special attention to enough safe distance.
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