PCB printed circuit board density is becoming higher and higher, the quality of PCB design against interference ability has a great impact, so PCB layout is in a very important position in the design. Layout requirements of special components:

1, the shorter the connection between high-frequency components, the better, to minimize the electromagnetic interference between each other; Easily disturbed components should not be too close to each other; Input and output components should be as far away as possible;

2, some components have a higher potential difference, should increase the distance between them, reduce the common mode radiation. The layout of components with high voltage should pay special attention to the rationality of the layout;

3, thermal elements should be far away from heating elements;

4, the capacitor should be close to the chip power pin;

5, the layout of the potentiometer, adjustable inductor coil, variable capacitor, micro-switch and other adjustable components should be placed in easy to adjust the position according to the requirements;

6, should set aside the printed board positioning hole and fixed bracket occupied by the position.

Layout requirements of common components:

1. Place the components of each functional circuit unit according to the circuit process to make the signal flow direction as consistent as possible;

2. Take the core components of each functional circuit as the center to carry out layout around it. Components should be evenly and neatly arranged on the PCB to minimize and shorten the leads and connections between components;

3. For circuits working at high frequencies, interference between components should be considered. In general circuits, components should be arranged in parallel as far as possible to facilitate wiring;

4. The outplace line of PCB is generally not less than 80mil from the edge of PCB. The best shape of the circuit board is a rectangle with a 3:2 or 4:30 aspect ratio.