Complete PCB layout rules

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This section describes the PCB wiring and some common rules for PCB painting. When you use PCB layout, you can refer to these materials to draw a high-quality PCB. Of course, you can also flexibly adapt to your actual needs.

This is a complete PCB layout design rule, from the layout of components to component arrangement, to wire wiring, and line width and spacing, there are also pad, have made a detailed analysis and introduction, below is the introduction of this Article

I,Component Layout
The layout of Components in PCB design rules includes: component layout requirements, component layout principles, component layout sequence, and common component layout methods.

Ii. component arrangementThe arrangement of components on the PCB can adopt one of the three arrangement methods, such as irregular, rule and grid.

3. Component spacing and installation sizeIt is about the gap between elements and the size of the installation during the discharge of components in the PCB design.Iv. Wiring of printed wiresWiring refers to the placement of the trend and shape of printed wires. It is the most critical step in PCB design and is the most labor-intensive step.5. Width and spacing of printed wires

Width and spacing of printed wires. Generally, the minimum width of the wires is 0.5-0.8mm, and the spacing is not less than 1mm. Vi. Size and shape of padThis section describes the basic knowledge of PCB design, including the shape of the pad and the welding hole size.

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Layout of components based on PCB layout design rules

Source: Electronic craft Author: xixiquan Date: 23:27:09
The layout of Components in PCB design rules includes: component layout requirements, component layout principles, component layout sequence, and common component layout methods.

 

InPCB layout, We useProtel, dxp, pads, Protel dxpWhen drawing a circuit board using tools, pay attention to the following aspects:
(1) component layout requirements

Ensure the circuit functions and performance indicators; meet the requirements of technology, testing, maintenance, and other aspects; the components are arranged neatly and properly, while taking into account the aesthetics. PCB Resources Network-p c B resource Source Network

(2) Principle of component Layout

The arrangement orientation should be as consistent as possible with the schematic diagram, And the wiring direction should be the same as the wiring direction of the circuit diagram;PCB5-10mm gaps left around the device; layout components should be conducive to heat dissipation components; high frequency, to consider the distribution parameters between components, the general circuit should try to make the components in parallel; isolation is required between high and low voltage, and the isolation distance is related to the withstand pressure on the PCB source network-p c source network.

For single-sidedPCBEach component pin exclusively uses a pad, and the components cannot cross up or down. The adjacent two components must be kept at a certain distance, not too small or touch.

(3) component layout Sequence

First place the components that occupy a large area; first integrate and then separate; first master and then multiple integrated circuits, first place the main circuit.

(4) Layout of common components

PCB resources-p c B resource source network adjustable components should be placed on the printed board for easy adjustment; components with a quality of more than 15 GB should be supported, high-power devices should be best installed on the chassis of the entire machine, thermal components should be away from heating components; for tubular components generally adopt flat, but the PCB size is not big, can adopt vertical, generally, the spacing between the two pad is 0.1-0.2 in (1 in = 25.4x10 (-3 cubic) M). For the integrated circuit, you must determine whether the positioning slot is correctly positioned.

Arrangement of components based on PCB design rules

Source: Electronic craft Author: xixiquan Date: 23:35:56
The arrangement of components on the PCB can adopt one of the three arrangement methods, such as irregular, rule and grid.

 

(1) Irregular Arrangement

The axis directions of components are inconsistent with each other, which is convenient for layout of printed wires, and the plane utilization is high and the distribution parameters are small, which is especially beneficial to high-frequency circuits.

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(2) Rule Arrangement

The axes of components are arranged in the same direction, and the layout is beautiful and neat, but the cabling is long and complicated, and suitable for low frequency circuits.

(3) grid Arrangement

Each installation hole in the grid arrangement is designed at the intersection of the square grid. InCAD (Auto CAD, orcad)In the software, the interpoint spacing Division is in meters (metric) or imperial (:Imperial). PCB Resources Network-p c B resource Source Network

 

PCB design rules-component spacing and installation dimensions

Source: Printed Circuit Technology Author: Xia xiquan Date: 23:38:32
It is about the gap between elements and the size of the installation during the discharge of components in the PCB design.

 

(1) PIN spacing of components

Different components have different pin spacing. But most of the pin spacing for various components is: an integer multiple of 100mil (Imperial) (1mil = L x 10 (-3 cubic) in = 25.4x10 (-6 power) m), usually mil as 1 spacing. PCB Resources Network-p c B resource Source Network
In PCB design, the pin spacing of components must be precisely identified because it determines the pad placement spacing. The most direct method for determining the pin spacing of non-standard devices is to use a vernier caliper for measurement. Pin spacing of common components. PCB Resources Network-p c B resource Source Network

Pin spacing of common components
A) Dip ic B) to-92 type transistor C) 1/4 W type resistor d) a fine-tuning Resistor

(2) component installation dimensions

The gap between the weld holes is determined based on the pin spacing. It has soft and hard sizes. The soft size is based on the components that can be bent by the pin. Therefore, the welding hole distance of this type of device is flexible. The hard size is based on the components that cannot be bent by the pin, and the welding hole distance requirement is quite accurate. When designing a PCB, the determination of the welding hole spacing of components can be measured by a scale measurement tool in the CAD software. PCB Resources Network-p c B resource Source Network

Printed wire cabling Based on PCB design rules

Source: Printed Circuit Technology Author: Xia xiquan Date: 23:50:49
Wiring refers to the placement of the trend and shape of printed wires. It is the most critical step in PCB design and is the most labor-intensive step.

 

PCB wiring includes single-sided wiring, double-sided wiring, and multi-layer wiring. There are also two types of wiring: Automatic wiring and manual wiring. The trend and shape of printed wires are shown in the table.
In the PCB design, the following basic principles should be followed to achieve satisfactory wiring results:

1) printing line direction-as straight as possible, to short better, do not detour.

2) bending of the printed line-the line is smooth and natural, and the corner is used for the connection to avoid right angles.

3) printed wires on the double panel-the wires on both sides should not be parallel to each other; printed for circuit transmission and Output

The wires should avoid parallelism as much as possible, and it is best to add a ground wire to the PCB Resource Network-p c B resource source network between these wires.

4) printed wires are used as ground wires-copper foil is kept as much as possible as a public ground wire and arranged on the edge of the PCB.

5) use of large-area copper foil-it is best to hollow out a grid when using it, which is conducive to eliminating the volatile gas produced by the heat of the adhesive between the copper foil and the substrate. When the width of the wire exceeds 3mm, the middle is left in the trough, to facilitate the source network of the welding PCB resources-p c B.

Trend and shape of printed wires

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PCB design rules-width and spacing of printed wires

Source: Printed Circuit Technology Author: Xia xiquan Date: 0:00:27
Width and spacing of printed wires. Generally, the minimum width of the wires is 0.5-0.8mm, and the spacing is not less than 1mm.

 

(1) minimum width of printed wires

It is mainly determined by the adhesion strength between the wire and the insulation substrate and the current value flowing through them. PCB power cord and ground wire due to large electrical flow, the design should be appropriately widened, generally not less than 1mm, for PCB installation density is not large, printed wire width is best not less than 0.5, the size of the manual board shall be no less than 0.8mm. PCB Resources Network-p c B resource Source Network

(2) printed wire spacing

It is determined by the safe operating voltage between them. The peak voltage between adjacent wires, substrate quality, surface coating layer, and capacitance coupling parameters all affect the safe operating voltage of printed wires.

To meet electrical safety requirements, the width and gap of printed wires are generally no less than lmm. PCB resources-p c B Source Network

PCB design rules-size and shape of pad

Source: Unknown, Printed Circuit Technology Author: Xia xiquan Date: 0:04:40
This section describes the basic knowledge of PCB design, including the shape of the pad and the welding hole size.

 

Size of pad

The outer diameter of the pad determines the size of the pad, expressed in D; the diameter of the pad is determined by the component lead diameter, the thickness of the metallic plating hole, etc., expressed in D, generally not less than 0.6, otherwise, it is not easy to process the die opening and punching. For single panel d ≥ (D + 1.5) mm; for dual panel d ≥ (D + 1.0) mm

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