How to layout components when design a printed circuit board?

The layout of the printed circuit board is the placement of the components on the board. In the manufacturing of printed circuit boards, the layout of components is very important. On the printed circuit board, only the reasonable layout of the components and connections can make the whole machine work reliably; otherwise, all kinds of interference may occur, thus reducing the technical index of the whole machine. Some layout can meet the requirements of relevant technical parameters, but the entire layout is uneven, messy, will also hinder the assembly and maintenance of products, this design is also unreasonable. Therefore, it is an important part in the design of printed circuit board to arrange the components reasonably so that the performance of the whole device is good and the layout is neat and beautiful.

1. Layout requirements and principles

When the layout of printed circuit board is designed, it is necessary to ensure the basic function and electrical performance of the circuit, and to facilitate the production, maintenance and use of the product. In addition, in the absence of strict size requirements, to make the layout of both beautiful, components as neat and compact as possible.

The following principles shall be followed in the layout of components.

(1)The principle of proximity.

Consider the shape and size of each component, positive and negative, and the number of pins, with short wires as the best way to adjust their position and direction. Components related to a functional area should be placed together.

(2)Signal flow principle.

The whole circuit is divided into several circuit units according to its function and placed according to the direction of the signal.Easy to install and check the circuit. The position of each circuit unit of the signal. This way. Even if the layout of the whole board is clear at a glance.'

(3) The principle of heat dissipation.

Printed circuit board substrate does not withstand temperature and low thermal conductivity.

The working temperature of the main printed circuit board should not exceed that of the printed circuit board,85°C .

In structural design, it is possible to use uniform and distributed thermal loads, and components with embossed heat devices in printed boards and components with a focus on the heating components should be prioritized in the presence of heat is dissipated by means of banded heat conduction strips, partial or total forced air cooling and so on.

A position conducive to heat dissipation. If necessary, separate heat receptacles may be provided to lower the temperature and reduce the impact on adjacent components. The radiator of the transistor or rectifier element can be directly mounted on its shell or the radiator can be fixed to the printed circuit board the chassis or the machine base plate. The high-power resistor can use the good heat conduction 1 ~ 3mm thick aluminum plate to write the curved surface roundness, clings to the resistor's shell, and fixed, in order to dissipate the heat. For the thermal sensor, it should be far away from the high temperature area, or the wall structure should be used to disconnect the heat source from the heat source to avoid the influence of the heating element. A large power dissipation integrated circuit, medium / high power transistor, resistor and other components, should be arranged in a place where heat is easy to dissipate, and separated from other components a certain distance.

4) Arrangement sequence.

The main devices are distributed first and then the main devices of each functional circuit are distributed first, and then the other secondary devices are arranged around the main devices.

For example, in a transistor circuit, the position of the electrodes of the transistor is arranged first, and then other circuits are arranged according to the wiring of each electrode. The first is to put the larger device and then the small device. The special device is to determine the location of the special device and then set up other components. The special device here refers to the device which has a great impact on the overall performance of the product. The position of the device has been fixed and can not be changed when the device is designed.

This article is from Allicdata Electronics Limited.