What Is High TG PCB?

High TG PCB, also called High Tg PCB or high temperature PCB, is a printed circuit board manufactured with laminate material that has a higher glass transition temperature. TG means Glass Transition Temperature. It is the temperature range where the PCB laminate changes from a rigid glassy state to a softer rubber-like state.

When PCB material operates near or above its Tg value, dimensional stability, mechanical strength, insulation performance, and plated through hole reliability may be reduced. For products exposed to high assembly temperature, high operating temperature, repeated thermal cycling, or high reliability requirements, High TG PCB material is often recommended.

Common PCB Tg Values

Material Type	Typical Tg Value	Common Use
Standard FR4	130°C - 140°C	General electronic products and standard PCB fabrication
Mid Tg FR4	Around 150°C	Moderate thermal reliability requirements
High Tg FR4	170°C	Lead-free assembly, multilayer PCB, industrial electronics, and reliability products
High Tg FR4	180°C	Higher thermal stress, automotive electronics, power electronics, and high reliability PCB
Advanced High Temperature Material	200°C or higher	Special high temperature or advanced engineering applications upon review

Benefits of High TG PCB Fabrication

Benefit	Explanation
Higher Thermal Stability	High TG material keeps better dimensional and mechanical stability under elevated temperature.
Lower Z-Axis Expansion	Reduced expansion in the board thickness direction helps improve plated through hole reliability.
Better Lead-Free Assembly Compatibility	Lead-free soldering uses higher process temperatures, and High TG PCB material can better handle thermal stress.
Improved Long-Term Reliability	High TG PCB is suitable for products exposed to thermal cycling, continuous heat, and demanding operating environments.
Better Multilayer PCB Stability	High TG material is often selected for multilayer PCB where lamination, drilling, plating, and assembly reliability are important.

High TG PCB Applications

• Industrial control systems
• Automotive electronics
• Power electronics and power supply boards
• Telecommunication and networking equipment
• Medical electronics and instrumentation
• High layer count multilayer PCB
• Lead-free assembly products
• LED, motor control, and high temperature operating electronics
• Thick copper PCB and high current PCB applications
• High reliability commercial and industrial products

High TG PCB fabrication is often selected when standard FR4 material may not provide enough thermal margin for assembly, operation, or long-term reliability. It is especially useful when PCB products must remain stable under repeated heating and cooling cycles.

High TG PCB vs Standard FR4

Item	Standard FR4 PCB	High TG FR4 PCB
Typical Tg	130°C - 140°C	170°C - 180°C
Thermal Stability	Suitable for general applications	Better stability under higher temperature
Lead-Free Assembly	May be acceptable for simple designs	Recommended for higher reliability lead-free assembly
Plated Hole Reliability	Good for standard thermal conditions	Better for thermal cycling and multilayer PCB
Typical Cost	Lower	Higher than standard FR4
Typical Products	General electronics	Industrial, automotive, power, network, and high reliability products

Our High TG PCB Capabilities

Item	Capability
Board Type	Single-sided PCB, double-sided PCB, and multilayer PCB
Layer Count	1-layer to 20-layer PCB upon engineering review
Material	High TG FR4, Tg170 FR4, Tg180 FR4, and other high temperature PCB materials upon request
Board Thickness	0.2mm to 6.0mm, depending on material, layer count, and design requirements
Copper Weight	0.5oz to 10oz copper, depending on board design and manufacturing review
Surface Finish	HASL, lead-free HASL, ENIG, OSP, immersion silver, immersion tin, and other options
Order Type	Prototype PCB and production PCB fabrication

When Should You Choose High TG PCB?

High TG PCB material is not required for every PCB design. However, it should be considered when the product faces high assembly temperature, high operating temperature, repeated thermal cycling, or strict reliability requirements.

• The PCB will go through lead-free reflow soldering.
• The board has many layers or a complex multilayer stack-up.
• The product operates in a hot industrial or automotive environment.
• The PCB uses heavy copper or carries high current.
• The design requires better plated through hole reliability.
• The product has long service life or high reliability requirements.
• The PCB must resist thermal cycling during operation.

Common High TG PCB Materials

High TG PCB materials are available from different laminate manufacturers. The exact material brand and grade may depend on availability, electrical requirements, thermal requirements, and customer specification.

Material Example	Typical Tg	Notes
High TG FR4	170°C	Common High TG PCB material for lead-free assembly and multilayer PCB
High TG FR4	180°C	Used for higher thermal reliability requirements
Shengyi S1000-2M or equivalent	Around 170°C	Commonly used High TG FR4 material or equivalent option
IT180A or equivalent	Around 180°C	Commonly used Tg180 material or equivalent option
Customer Specified Material	According to datasheet	Available upon engineering and purchasing review

High TG PCB Design Considerations

1. Confirm Operating Temperature

The PCB material should be selected based on the real operating temperature and the required thermal margin. A higher Tg value does not mean the PCB can operate permanently at that exact temperature, but it provides better material stability when compared with lower Tg FR4.

2. Consider Lead-Free Assembly Temperature

Lead-free soldering usually has higher reflow temperature than traditional tin-lead soldering. High TG FR4 is commonly selected to improve thermal robustness during assembly.

3. Review Layer Count and Board Thickness

Multilayer PCB fabrication requires lamination and drilling processes. High TG material can help improve mechanical and dimensional stability for multilayer boards, especially when the design includes dense vias or high reliability plated holes.

4. Check Copper Weight and Thermal Stress

Heavy copper PCB, power electronics PCB, and high current PCB may experience stronger thermal stress. High TG material is often used together with thicker copper to improve board reliability.

5. Match Material to Electrical Requirements

For controlled impedance PCB, high-speed digital PCB, RF PCB, or low loss applications, Tg is only one material parameter. Dk, Df, copper roughness, stack-up, and impedance requirements should also be reviewed.

High TG PCB and Lead-Free Assembly

Lead-free assembly is one of the most common reasons to choose High TG PCB material. Because lead-free soldering uses higher process temperatures, the PCB laminate may be exposed to more thermal stress during reflow, wave soldering, or rework.

High TG FR4 provides better resistance to softening, expansion, and thermal deformation. This can help reduce the risk of barrel cracking, delamination, pad lifting, and long-term reliability problems caused by heat.

High TG PCB and Multilayer PCB Reliability

Multilayer PCB boards often have many plated through holes, internal copper layers, and laminated dielectric layers. During thermal cycling, the different materials inside the PCB expand and contract. Lower Z-axis expansion can help reduce stress on plated through holes.

For 4-layer, 6-layer, 8-layer, and higher-layer PCB designs, High TG FR4 is often recommended when the board is used in demanding environments or requires better thermal reliability.

High TG PCB Quote Information Required

To quote a High TG PCB accurately, please provide complete fabrication data and material requirements.

• Gerber files and drill files
• Board quantity
• Layer count
• Finished board thickness
• Copper weight
• Required Tg value, such as Tg170 or Tg180
• Specific material brand or equivalent material acceptance
• Surface finish requirement
• Solder mask color and silkscreen color
• Special reliability, temperature, or assembly requirements

High TG PCB FAQ

What does Tg mean in PCB?

Tg means Glass Transition Temperature. It is the temperature range where PCB laminate material begins to change from a rigid glassy state to a softer rubber-like state.

What is considered High TG PCB?

In common PCB fabrication practice, Tg170 and Tg180 materials are usually considered High TG FR4 materials. Some special materials may have Tg values of 200°C or higher.

Is High TG PCB required for lead-free assembly?

High TG PCB is not always mandatory, but it is often recommended for lead-free assembly, especially for multilayer PCB, thick copper PCB, high reliability products, or boards exposed to repeated heating.

What is the difference between Tg170 and Tg180?

Tg180 material has a higher glass transition temperature than Tg170 material and may provide better thermal margin. The best choice depends on product operating conditions, assembly process, reliability requirements, and cost target.

Is High TG PCB more expensive than standard FR4?

Yes. High TG FR4 material normally costs more than standard FR4. However, for high reliability or high temperature applications, the improved thermal performance may reduce the risk of failure.

Can High TG PCB be used with controlled impedance?

Yes. High TG FR4 can be used for controlled impedance PCB. For impedance controlled designs, the stack-up, dielectric thickness, Dk value, copper thickness, trace width, and trace spacing should be reviewed together.

Can High TG PCB be used for heavy copper PCB?

Yes. High TG material is often a good option for heavy copper PCB and power electronics PCB because these boards may experience higher thermal stress during assembly and operation.

Do I need to specify the exact High TG material brand?

If your project requires a specific material brand and grade, please specify it clearly. If equivalent material is acceptable, please state that equivalent High TG FR4 material can be used.

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