Printed circuit board assembly
1 Purpose and role
1.1 specification design operations, increase productivity and improve product quality.
2 Scope
1.1 XXX Super VCD developed by the Ministry of VCDDVD audio products.
3. Attitude of responsibility
3.1 XXX Development of all electronic engineers, technicians and computer draftsmen.
4 qualifications and training
4.1 electronic technology base; 4.2 with basic computer operation knowledge; 4.3 PCB familiar with the use of computer graphics software.
5 Guiding (with length unit MM)
Minimum line width of copper foil 5.1: 0.1MM, 0.2MM edge panel smallest copper foil to 1.0MM 5.2 minimum clearance: 0.1MM, panel: 0.2MM. 5.3 Copper and board side as the minimum distance 0.55MM, components and board side minimum distance of 5.0MM, side plate and the plate is generally the minimum distance 4.0MM 5.4 through-hole component pad size (diameter) hole twice, double-sided minimum 1 .. 5MM, single-sided minimum 2.0MM, Yee (2.5MM) if you can not use round pads, round pads with waist, small as shown below (if any standard libraries, places subject to the standard library) pad long side, short side of the relationship with the hole as follows: 5.5 Electrolytic capacitor not touch heating elements, power resistors, thermistors, pressure, heat, etc.. capacitive solution with a minimum interval of the radiator 10.0MM, its components to a minimum interval of the radiator 2.0MM. 5.6 Large components (such as: transformers, diameter 15.0MM over electrolytic capacitors, high current sockets, etc.) to increase the area of ??copper and tin on the following map; shaded area of ??fat pad area with the same minimum. Within a radius of 5.0MM 5.7 screw holes can not have a copper foil (required ground outside) components. (According to chart required). 5.8 can not have a bit of tin on the oil screen. 2.5MM 5.9 pad center distance is less than the adjacent pad oil should be wrapped around the screen, ink width 0.2MM (Yee 0.5MM). 5.10 below the IC jumper or not motors, potentiometers, and other large volume metal components under. 5.11 PCB design in a large area (about over 500CM2 above), to prevent over bending the printed circuit board assembly when tin stove, leaving the middle of the PCB board width of a gap between 5 and 10MM hold components (alignment), when used in the Tin stove to prevent the PCB bending with the pressure of , below the shadow:: 5.12 per one transistor must be marked on the screen e, c, b feet. 5.13 after welding needs Tin stove components, tin plate to open the place to go to the direction and over-tin On the contrary, the degree depending on the size of the hole as shown for the 0.5MM to 1.0MM: 5.14 dual-panel design should pay attention to, metal components, plug-in shell in contact with the PCB, the top of the pad can not be open, be sure to use green oil or oil-covered screen (such as the feet of the crystal). 5.15 In order to reduce solder shorts, all double-sided PCB, through-hole green oil window is not open. 5.16 each piece on the PCB assembly must be marked with the solid arrow direction over tin stove: 5.17 minimum distance between holes 1.25MM (dual-panel invalid) 5.18 layout, DIP IC package must be placed over the direction of the direction of tin furnace into a vertical, not parallel, as shown; difficult if layout that allows horizontal IC (OP package IC DIP placed opposite direction). 5.19 for horizontal or vertical routing direction from the vertical into the horizontal 45 degrees to go into. 5.20 components placed horizontally or vertically. 5.21 screen printing characters placed horizontally or turn right 90 degrees. 5.22 If the width of copper foil into a round pad pad diameter than the round hour, you need to add a teardrop. Figure: 5.23 coding, and design code to be placed on board the space. 5.24 where there is no reasonable connection for ground or power supply. 5.25 as short as possible, pay special attention to the clock lines, low frequency signal line and all the circuit wiring to be shorter. 5.26 analog and digital circuit ground and power supply system to be completely separate. 5.27 If there is a large area of ??ground on the PCB and the power line area (an area of ??more than 500 mm2), should be partially open window. Figure: 5.28 PCB electrical plug holes as follows, can not put the shaded components, except for hand-inserted components, L is the range of 50 330mm, H in the range 50 250mm, if less than 50X50 mold will have to puzzle before electrical plug, if more than 330X250 is to hand flapper. In the long edge of the hole to be positioned. Edit this paragraph the basic concepts of PCB design