PCB Trace Width Calculator: The Ultimate FAQ Guide

If you have any question about PCB trace width calculator, your answer is right here.

This guide will help you understand everything you need to know about PCB traces.

 

Keep reading to learn more.

What is a PCBs Trace Width?

PCB trace width

 PCB trace width

The width of a PCB trace is a parameter that defines the distance across a trace on a circuit board.

Other notable trace parameters are the trace spacing and thickness.

You find the PCB trace width to be influenced by:

  • The required current carrying capacity of the trace.
  • The size of the conductive layer on the board.
  • The required spacing between the traces.
  • The desired trace length.

What is a PCB Trace Width Calculator?

A PCB trace width calculator is a tool derived from the IPC-2221 standard used to calculate a PCB’s conductive track width.

The calculated copper width, at a given thickness, is determined to allow the transfer of a specified current value.

Furthermore, the copper width and thickness should be sufficient to maintain the temperature rise at a level below the determined input.

 PCB trace width calculator

PCB trace width calculator

How do you Determine the Trace Width using the PCB Trace Width Calculator?

The PCB trace width calculator requires the input of specific values to establish the desired width of the trace.

The width is provided in mils and involves the use of the following values:

  • The cross-sectional area of the conductive layer given in mils squared.
  • The thickness of the trace in ounces per square foot.

What is the Difference Between the Internal and External PCB Trace Width Calculator?

The internal PCB trace width calculator is a tool for determining an internally located trace’s required width.

The internal trace width is determined to carry a particular current amount.

The external PCB trace width calculator is a similar tool that determines the width of an external trace.

The determined trace width is also used for the current transfer of a specific amount.

Consequently, you find the difference between the internal and external traces in their location relative to the board’s substrate.

Why is the PCB Trace Width Calculator Necessary?

When making printed circuit boards, you find that current-carrying limitations are a significant constraint.

You can trace a board only to discover later that it cannot effectively carry the required current amount.

Consequently, the intended application of the circuit board is hampered by the inadequacy in current capacity.

Using a PCB trace width calculator is a sure way of ensuring the conduction of the appropriate current value.

With this tool, you can use your desired maximum current rating to determine your trace’s width.

Furthermore, you can influence the temperature rise recorded by your PCB by employing a PCB trace width calculator.

What is meant by Temperature Rise in PCB Trace Width Calculation?

When current flows through the conductive trace, heat is generated due to the resistance to the current flow by the conductor.

The generated heat is defined by a temperature increase, which is referred to as temperature rise.

You can determine the amount of temperature rise your PCB can sustain by using the PCB trace width calculator.

By providing wider PCB trace widths, you can reduce the amount of heat buildup and, subsequently, temperature rise.

Ten-degree temperature rise is considered a safe value for many circuit boards.

Otherwise, boards can be fabricated to withstand higher temperature rise values.

You also find the environment of application to influence the overall board temperature.

Can other Measurements be Extracted Via the use of a PCB Trace Width Calculator?

A PCB trace width calculator helps establish other different measures of a printed circuit board.

Extra input parameters can be included, such as the length of the trace and operating temperature to extract more measurements.

As a result, you can also determine the following measures:

  • The temperature rise of the trace
  • The resistance value of the trace
  • The voltage drop across the trace
  • Dissipated power along the trace

Are Board Spokes Subject to PCB Trace Width Calculation?

PCB spokes or wagon wheels are board design features meant to simplify the soldering process for ground planes.

They resemble traces but are short in length and typically dug into the plane.

When using a PCB trace width calculator, considerations for the spoke are usually not made since not all boards feature them.

However, it is customary to make spokes to a lesser width than the actual traces though not based on calculations.

Is the Cross-sectional Conductive Layer Area a useful Parameter in the PCB Trace Width Calculation?

Yes, it is.

The cross-sectional area of the conductive layer is a vital input in determining a PCB trace width calculator.

The area is provided in mils squared and used as a numerator for trace width division calculation.

To determine the cross-sectional area of the conductive layer, you require:

  • The maximum allowed current measured in Amperes.
  • The maximum allowed temperature rise in degrees centigrade.
  • Three constant values, k, b, and c, differ when the traces are internal or external.

What are the Constant Values for in PCB Trace Width Calculator?

When calculating the PCB trace width, you have to determine the cross-sectional area of the conductive layer.

The area is determined by using three constant values: k, b, and c, derived from the IPC-2221 standard document.

You find these constant values are provided as conductive material requirements.

Additionally, these constants’ values differ depending on the trace location, that is, whether external or internal.

How is the Overall Temperature of the Trace Determined in the PCB Trace Width Calculator?

The overall trace temperature is useful in determining the thermal performance of your printed circuit board.

You can establish your overall trace temperature by summing the maximum desired rise in temperature and the ambient temperature.

All the temperature values are provided in degrees Celsius.

Can you Determine the Trace Resistance using the PCB Trace Width Calculator?

The PCB trace width calculator can help you establish the resistance value of your traces.

After determining the trace width using the PCB trace width calculator, you can establish the resistance value.

Use of the trace width will be alongside the following parameters:

  • The cross-sectional area (A) of the conductive layer in square centimeters.
  • The thickness of the trace (T) in ounces per foot square.
  • The resistivity value for the conductive material (ρ) in ohm-centimeter.
  • The length of the trace (L) in centimeters.
  • The temperature coefficient resistivity of the conductive material (α) given per degree Celsius.
  • The overall trace temperature (TTEMP) in degree Celsius.

Are the Voltage Drop and Dissipated Power affected by the PCB Trace Width Calculator?

PCB Trace Width

PCB Trace Width

Calculating the voltage drop across the trace and the dissipated power is independent of the trace width.

However, both the voltage drop and the power loss are determined using the maximum current value and resistance value.

The voltage drop on a trace is determined by the maximum current and the overall resistance value.

Alternately, the power loss is determined by the product of the resistance value and the square of maximum current value.

Given a PCB Trace Width, can you Determine its Current Carrying Capacity?

Yes.

You can calculate the amount of current a given PCB trace width can carry by various methods.

Two common approaches are using a PCB trace current calculator or using the PCB width calculator and working backward.

Determining the board’s current carrying capacity is helpful when you need to check your board’s application limit.

Establishing the PCB trace width’s current limitations will ensure you don’t subject the board to potentially damaging use.

How do External and Internal Trace Widths compare when using the PCB Trace Width Calculator?

The distinction between internal and external traces lies in their location.

External traces are located on the outer PCB surfaces, while internal traces are located on the inner PCB layers.

When using the PCB trace width calculator, you find internal traces are significantly wider than external traces.

In calculating trace width, the values for the necessary parameters for both external and internal traces may differ.

These parameters include the copper thickness, cross-sectional area, and the constant values for conductive material.

You find that the difference results from the construction differences and different thermal requirements.

A significant role of the PCB trace width calculator is to regulate the temperature rise.

External traces are exposed, allowing generated heat to be lost partly through convection.

Conversely, internal layers are blanketed by non-conductive layers resulting in heat accumulation.

It follows that the internal traces need to be wider to increase the surface area for heat dispersion.

What is a mil in PCB Trace Width Calculator?

A mil is a unit of measurement employed in the PCB trace width calculator.

It is a small measure that is equivalent to a thousandth of an inch.

The use of mils has been standardized in the PCB industry, primarily when referring to the board layer thickness.

Copper thickness, while expressed as weight in ounces, can also be converted to mils.

Is using a PCB Trace Width Calculator the only Determinant for Current Carrying Capacity?

The PCB trace width calculator’s role in determining the amount of current a conductive trace can accommodate is undeniable.

However, you find other board features and elements that contribute to the traces’ current-carrying capability.

For instance, a pads and vias system significantly influences the current amount that can pass through a trace.

Conductive vias offer alternative routes for current flow, allowing for narrower traces to be made.

As a result, you can have a large circuit density enhancing the board’s performance capabilities.

Furthermore, the number of attached components onboard will considerably contribute to trace current flow.

You find some electrical components that have immense power demands with great thermal dissipations.

As you can see the PCB trace width calculator plays an integral role in PCB fabrication process.

For any questions or inquiries about PCB trace width, contact Venture Electronics now.

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