Pls does anyone know the formula for calculating the PCB routing width, thanks

Calculate according to the impedance you require.

The following is the information of the usual collection:

Crystals, crystal oscillators, relays, switching power supplies and other strong radiation devices should be at least 1000 mils away from the single board interface connectors;

Ground wire power line signal line, usually the signal line width is: , the most thin width can be reached, the power line is mm The PCB of the digital circuit can be used with a wide ground wire to form a loop, that is, to form a ground network to use (the ground of the analog circuit can not be used in this way) Use a large area of copper layer as a ground wire, and connect the unused places with the ground on the printed board as a ground wire.

The power cord should be as wide as possible, not less than 18mil; The signal line width should not be less than 12mil; CPU inlet and outlet lines should not be lower than 10mil (or 8mil); Line spacing is not less than 10mil;

1. First of all, the width of the PCB power cord should be above 40mil, and the minimum should be above 25mil, and the width should be as wide as possible if conditions permit;

2. In addition, the actual current should be considered, generally the maximum current that 10mil can withstand is 1A, and the appropriate line width is selected according to the actual current;

3. The ground wire of the power supply should be wider than the line width of V+, and try to surround V+ to reduce interference and power ripple;

4. Converted to mm, it can be simply recorded as the positive power supply is not lower than, the negative power supply is greater than the positive power supply, and it is surrounded by the positive power supply.

20 30 mil

If possible, be as wide as possible and pour copper.

It depends on how much current you have. Anyway, the wider the better...

PCB trace width

For general low-frequency and small current, 10mil is selected, and 6mil is selected for special density.

The width of the PCB traces determines the factor

The size of the current: the line with a large current should be wider, and the line with a small current can be thinner.

The level of working frequency: the working frequency can be thin if the working frequency is low, and the working frequency should be appropriate if it is high, and it is not too fine or too thick.

The size and complexity of the plate area: the line with a simple plate and a large area can be thicker, and vice versa.

1. Precautions for PCB layout

The first principle of the layout is to ensure the throughput rate of the wiring, pay attention to the connection of the flying wires when moving the device, and put the devices with the connection relationship together.

Digital and analog devices should be separated and kept as far away as possible.

The decoupling capacitor is as close as possible to the VCC of the device.

When placing the device, consider later soldering and not too dense.

Use the array and union functions provided by the software to improve the efficiency of the layout.

2. Precautions for PCB wiring

Make the power cord and ground wire as bold as possible.

The decoupling capacitor should be connected directly to the VCC as much as possible.

When setting the do file of specctra, first add the protect all wires command to protect the hand-laid wires from being rerouted by the autorouter.

If there is a hybrid power plane, it should be defined as a split mixed plane, split before routing, and after routing, use Pour Manager's Plane Connect for copper pouring.

Set all device pins to hot pad mode, set filter to pins, select all pins, modify the attributes, and tick the thermal option.

When routing manually, turn on the DRC option and use dynamic routing.

This depends on the specific application, the general low-frequency small current, the choice of 10mil can be, there is no need to be too fine, special dense situation, choose 6mil, no matter how small it is not suitable for processing, as far as possible more than 10mil, the processing cost is low, the process requirements are small, the current increases to the above, it needs to be calculated according to the thickness of the copper pour and the cash payment.

If it is just an ordinary two-layer board, there is no problem with setting the wiring width to 8mil, that is, probably, if the wiring is relatively dense multi-layer board, the board factory can process 5mil line, that is, the processing equipment of the two-layer board is generally not as high as the multi-layer board, so it is appropriate to go thicker.

The above is the most detailed case, if conditions permit, it is no problem to walk 10mil or 15mil.

If you need to do very fine, such as 4mil, you can also do it, but it will be about 20% more expensive.

The digital signal line is 10mil or 15mil, it is recommended to use 15mil, and it is not easy to break the wire when making the board.

The power line and analog signal line are calculated according to the current, and the general circuit board uses a copper foil thickness of 35um (i.e. 1oz), which can be calculated as 1 square millimeter over 30A current (i.e., about 40mil line width over 1A current).

You can also search the web for a PCB linewidth calculator that takes into account the temperature rise. However, based on personal experience, I feel that the line width calculated by it is a bit narrow, and the copper foil used at home and abroad may be different, and the conductivity is different.

You're in the champion position, and I'll buy you a few oranges.

The role of the network system in cabling In many CAD systems, the wiring is determined by the network system. The mesh is too dense, and although the pathways have increased, the steps are too small, and the graph field is too small.

The amount of data is too large, which will inevitably have higher requirements for the storage space of the equipment, and it also has a great impact on the computing speed of computer electronic products. And some pathways are none.

Effective, such as occupied by the pads of the component legs or by mounting holes, stator holes, etc. The grid is too sparse and there are too few paths, which has a great impact on the distribution rate. So there has to be a sparse.

Reasonable mesh system to support the routing process. The distance between the legs of a standard component is inches (, so the basis of the grid system is generally set to inches.

mm) or integer multiples less than inches, such as: inches, inches, inches, etc.

6. Design rule check (DRC) After the wiring design is completed, it is necessary to carefully check whether the wiring design conforms to the rules formulated by the designer, and at the same time, it is also necessary to confirm that the rules formulated are.

Whether it meets the needs of the printed board production process, the general inspection has the following aspects: line and line, wire and component pad, wire and through hole, component pad and through hole, through hole.

Whether the distance between the hole and the through hole is reasonable and whether it meets the production requirements. Whether the width of the power and ground wires is appropriate, and whether there is a tight coupling between the power supply and the ground wires (low wave impedance.

Is there still a place in the PCB where the ground wire can be widened? Whether the best measures have been taken for the critical signal lines, such as the shortest length, plus the protection cables, input lines and output lines.

Road. Modify some undesirable line shapes. Is there a process line on the PCB? Whether the solder mask meets the requirements of the production process, whether the size of the solder mask is appropriate, and the character mark.

Whether it is pressed on the device pad so as not to affect the quality of the electrical set. Whether the edge of the outer frame of the power supply stratum in the multi-layer board is reduced, such as the copper foil of the power stratum is exposed outside the board, which is easy to cause shortness.

Road. Overview The purpose of this document is to illustrate the process and some considerations for PCB design using PADS's PCB PCB for a working group.

Designers provide design specifications to facilitate communication and mutual checks between designers.

Generally, the PCB is 1oz copper thickness, and the wiring width formula is 1A current to be 40mil line width (about 1mm).

If it is 2oz copper thickness, the formula is 1A current line width, and generally only high power uses 2oz copper thickness.

k is the correction coefficient, generally the copper clad wire is taken in the inner layer and in the outer layer; t is the maximum temperature rise in degrees Celsius (the melting point of copper is 1060);

A is the cross-sectional area of copper plush, and the unit is square mil (not millimeter mm., note that it is square mil.))；i is the maximum allowable current in amps

The original PCB board is a whole piece of copper foil on the surface.

According to the customer's needs, use chemical or other methods to go out of the unwanted parts, and form a copper foil trace on the board, the line width is the width of the line, and the line spacing is of course the line spacing.

Generally speaking, the production capacity will refer to the minimum line width and line spacing that can be made.

Line width refers to the width of the thinnest line on the PCB board, and line spacing refers to the distance between the two nearest adjacent lines on the PCB board. The units commonly used are millimeters (mm), mils (mil), and 1mil=. The line width and line spacing that you talk about when talking to customers are the minimum line width and line spacing that your company can produce.

Usually go down to the production line to understand it.

1.Line width and line spacing are two different concepts;

2.This concept can be understood with the help of water pipes, which are like laying water pipes on a piece of yellow earth.

The wider the line, the greater the current that can be passed, but the more space it occupies.

Line spacing, the distance between the two water pipes, can not be too close, if it is too close, it is not good to dig a ditch to release the water pipe.

3.Just to give an example, the official explanation is this:

The PCB board is a printed circuit board, and the original PCB board is a substrate that is covered with metallic copper on one side. The PCB wiring is on this copper surface, drawing the wire to retain the metal copper, and the rest is corroded.

The wire width should not be too thin, and if it is too thin, the wire may break when it is corroded.

The line spacing should not be too small, the two wires are too close, and it may not be clean when corroded, and it will be short-circuited directly.

The specification of strong and weak electric distance requires that it cannot be co-managed and slotted, and the distance should be about 50cm.

Conceptually speaking, strong electricity and weak electricity are generally easy to distinguish, and the main difference is the difference in use. Strong electricity is used as a power energy source, and weak electricity is used for information transmission.

1) The frequency of communication is different.

The frequency of strong electricity is generally 50Hz (Hertz), called "power frequency", which means the frequency of industrial electricity: the frequency of weak electricity is often high frequency or ultra-high frequency, measured in khz (kilohertz) and MHz (megahertz).

2) The transmission mode is different.

Strong electricity is transmitted by transmission lines, and weak current is transmitted by wired and wireless. Radios transmit electromagnetic waves.