How Thermal Pads and Paste Benefit PCB Design?

Printed circuit boards (PCB) are common to countless electronic devices, coming in the form of miniature assemblies with ICs and other components that facilitate standard operations. As PCB technology has continued to become more advanced and compact, the amount of heat generated per unit area has greatly increased. To best combat heat that can be detrimental to sensitive components, heat sinks are used for dissipation. For the most optimal cooling, thermal paste and thermal pad materials are implemented.

Thermal paste is beneficial for enhancing the connectivity of ICs and the heat sink thermal pad, allowing for the improved transfer of heat. Without thermal paste, heat can quickly collect in a single spot, surpassing safe operational temperatures and causing damage to the IC and surrounding elements. As a result, it is crucial that thermal pads and paste are implemented correctly.

The thermal pad itself is a large metal piece that may be bolted or soldered onto the PCB, featuring thermal conductivity for the means of transferring heat. A standard thermal pad is typically made from ceramic and silicone mixtures, and their placement is usually between a conductor of heat and the heat sink. Thermal pads known as thermal relief pads are also common to PCB design, and such components can assist in the soldering process of through-hole leads.

Thermal paste, on the other hand, is similar to thermal pads in the fact that they can conduct heat with ease. While in a liquid form, thermal paste consists of the same materials as thermal pads and can be placed in varying shapes to fit an area as required. For its placement, thermal paste is implemented between the heat sink and heat-generating device, ensuring that any air gaps present are filled and closed. This is very important as such pockets could easily hinder proper heat transfer and dissipation.

Depending on the system in question and various possible concerns, there are a few common considerations that should be made before making a purchasing decision. Generally, the most important factors that will affect the performance of a thermal paste include its thermal conductivity, viscosity, compatibility, pump-out resiliency, and dry-out resiliency. With a property such as viscosity, high values can result in substrate cracking if the module is devoid of a baseplate. Meanwhile, the dry-out resiliency of a paste is important if there is concern that it will begin to dry out over time and lose effectiveness.

Across all options, pastes that are silicone-based are typically the most highly recommended as they are well tested, cost-effective, high performing, and quite reliable. For silicone-freed pastes, synthetic fluids are often used for the carrier while metal oxide graphite or silver is implemented as the filler. Before application, pastes should always be mixed to ensure homogenization and a solvent can be added if needed..

While some assemblies may call for both a thermal pad and thermal paste in order for operations to be carried out with proper heat dissipation, many will only call for one or the other. Typically, the PCB manufacturer will conduct an assessment on the board, finding whether paste or pads will work best. When it comes time to begin sourcing the various PCB parts that you require for your operations, there is no better alternative to ASAP Parts Unlimited.

On our website, customers can receive competitive pricing on top components such as soldering pads, power supply products, thermal paste, heat sink parts, and so much more. Take the time to peruse our offerings at your leisure, and our team of industry experts is always on standby, ready to assist you with personalized quotes for your comparison. Get started on the purchasing process today and see why customers choose to rely on ASAP Parts Unlimited for all their operational requirements.