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PCB Substrates

Editorial Team - PCB Directory

Sep 15, 2019

Polyesters, also called Polyethylene Terephthalate (PET), are the most commonly used material to manufacture flexible PCBs. They are best-known for their flexibility, good electrical properties, and high chemical and moisture resistance.Key Characteristics:They have a melting point of 250ºC and a glass transition temperature of 80ºC.They have lower heat resistance that inhibits their use...read more

CEM-3 PCB Boards

PCB Substrates

Editorial Team - PCB Directory

Sep 15, 2019

Composite epoxy materials (CEMs) are made by combining two or more materials having different chemical and physical properties to achieve the desired substrate material with unique properties and characteristics. CEMs are generally used in PCBs as a substrate material.The PCB boards which use woven glass fabric and paper (cellulose) along with epoxy as the substrate material are called CEM-3 PCB b...read more

What are Copper Based PCBs?

PCB Substrates

Editorial Team - PCB Directory

Sep 14, 2019

Copper-based PCBs use copper as a primary base material in place of commonly used FR4. The copper base material is then covered with an insulating layer followed by a circuit layer. Copper core/based PCBs are known to have excellent heat dissipation and can be used for high frequency applications with minimal variation in performance over wide temperature ranges. However, these advantages do come ...read more

What are Aluminum-based PCB boards?

PCB Substrates

Editorial Team - PCB Directory

Sep 14, 2019

Aluminum-based Printed Circuit Boards use an Aluminum alloy as a base material for the PCB i.e. the dielectric layer is sandwiched between the Aluminum alloy and circuit layer. The Aluminum alloy is a composite of magnesium and silumin (Al-Mg-Si).Aluminum based PCBs are part of the Metal Core PCB family and deliver excellent thermal conductivity and insulation.Key Advantages of Aluminum Based PCBs...read more

What is Glass Transition Temperature (Tg)?

PCB Basics

Editorial Team - PCB Directory

Jul 13, 2019

Tg or the glass transition temperature is the temperature at which the base material of a PCB starts to transform from a brittle/rigid form factor to a soft, elastic one. The Tg value of a printed circuit board usually depends on the substrate used. This is one of the factors that you must consider when selecting the substrate materials for your PCB. You should make sure that the temperature where...read more

What is Loss Tangent?

PCB Basics

Editorial Team - PCB Directory

Jul 13, 2019

In PCBs, Loss tangent (tan (δ)) is the measure of signal loss due to the inherent dissipation of electromagnetic energy in the substrate of the printed circuit board. It is a dimensionless quantity and generally referred to: Loss Factor, Tan δ, Dissipation factor and Loss angle.All PCB materials have both conduction losses and dielectric losses. The conduction losses are resistive and ...read more

What are Composite Epoxy Materials (CEMs)?

PCB Substrates

Editorial Team - PCB Directory

Jul 12, 2019

Composite epoxy materials (CEMs) are made by combining two or more materials having different chemical and physical properties to achieve the desired substrate material with unique properties and characteristics. Epoxy synthetic resin is used to combine materials. It acts as a binding agent to hold the materials together. It also transfers the thermal stress between the materials and protects them...read more

What is Copper Weight in a PCB?

PCB Basics

Editorial Team - PCB Directory

Jul 12, 2019

Copper is one of the most important elements in PCB boards. Copper Weight or Copper Thickness in a Printed Circuit Board represents the thickness of 1 ounce of copper rolled out over an area of 1 square foot. For example, a PCB that has a copper weight of 1 oz will have a layer of copper that is 1.4 mils in thickness. Copper Weight is measured in ounces per square foot (oz/ft²).Copper Weight ...read more

What are Halogen Free PCB Boards?

PCB Basics

Editorial Team - PCB Directory

Jun 22, 2019

A Printed Circuit Board devoid of the halogen elements is called Halogen free PCB. Halogen elements are Chlorine, Bromine, fluorine, iodine, and Astatine which are very fatal to life. For a PCB to be considered “Halogen-Free” it must have less than 900 ppm of chlorine or bromine and a total of less than 1500 ppm of Halogen materials.In context to PCB manufacturing, the concerned haloge...read more

What is Solder Mask?

Editorial Team - PCB Directory

Jul 12, 2019

Solder mask or solder resist is a coating applied to a Printed Circuit Board (PCB) to protect the copper traces on the board and to stop electrical shorts. The solder mask is usually applied on both sides of the PCB i.e Top and Bottom to ensure reliability and performance.The solder mask is a Liquid UV Photo-imageable Ink which is usually green in color. Other color options like red, blue, yellow,...read more

What is the Silkscreen in a PCB?

Editorial Team - PCB Directory

Jun 22, 2019

The Silkscreen is the topmost layer of a Printed Circuit Board (PCB) which is used as a reference indicator for placing components on a PCB Board. It requires a specifically formulated ink whose standard color is white, but it can also be Red, Black, Yellow, Blue and a number of other colors.The silkscreen is used to specify useful information on the PCB board that can help/assist users during ass...read more

What is an Annular Ring?

Editorial Team - PCB Directory

May 18, 2019

A via is created by drilling a hole through a copper pad etched on each layer of a PCB. An Annular Ring is the area between the edge of the drilled via and the copper pad associated with that hole. The greater the width of an annular ring, the greater the copper connection around the drilled via will be.In a multilayer PCB, traces are routed from one layer to another layer with the help of vias. T...read more

What is DRC in Printed Circuit Boards?

Editorial Team - PCB Directory

May 18, 2019

Design Rule Checking (DRC) is a process used to identify errors and mismatches such as spacing & trace widths in a PCB design/layout. The layout of a PCB board is designed using software, each PCB fabricator has a set of rules which they publish that specify various parameters such as what the spacing between each line should be, the minimum size of vias, the width of a line etc.Once a design ...read more

What is a Blind Via?

Vias

Editorial Team - PCB Directory

May 18, 2019

Blind Vias connect the outermost layer of a multilayer PCB to a layer in the middle of the board. Blind vias can only be seen on one side of the board (that's where they get the name from). These vias enable designers to optimize their circuit layout by providing more space for routing. However, in comparison to Through-Hole Vias they are more difficult to construct and can cause the cost of c...read more

What is a Buried Via?

Vias

Editorial Team - PCB Directory

May 18, 2019

A Buried Via hole connects layers inside a multi-layer PCB. These vias cannot be seen on the surface of a Printed Circuit Board. Buried vias are difficult to construct, as they need to be created in layers within the PCB. Designers like to use these vias, as they do not take up board space on every layer, thereby enabling smaller PCBs.High-density PCBs use buried vias.

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