High-power RF, telecom, and industrial electronics keep pushing more current through smaller boards, and standard PCB thermal management techniques like copper pours and via arrays eventually run out of headroom. When that happens, engineers turn to embedded copper coins: a solid copper insert engineered to pull heat directly out of a hot spot instead of relying on the board's dielectric materials to do the job.
What Is an Embedded Copper Coin PCB?
An embedded copper coin PCB is a multilayer board with a solid, precision-machined block of copper inserted into the substrate, typically positioned beneath a high-power component. Rather than pushing heat sideways and downward through plated vias and copper planes, the coin provides a direct, low-resistance thermal path from the component pad through the board to a heat sink or chassis. Copper conducts heat hundreds of times more effectively than standard FR-4 laminate, so even a modest coin can outperform a much larger via farm.
Coins are installed one of two ways. Embedded coins are pre-cut into the layer stack and laminated in place during fabrication, making them the simpler, more cost-effective option. Press-fit coins are inserted after lamination and plating, contacting inner-layer copper directly for even better thermal transfer, though they demand tighter tolerances and more careful process control.
Why Thermal Management in Electronics Matters More Than Ever
As component density climbs and power devices shrink, thermal management electronics decisions increasingly determine whether a design survives its operating life. Excess heat accelerates solder fatigue, shortens component lifespan, and can cause RF and microwave circuits to drift out of spec. In systems where signal integrity is already tightly controlled, uneven heat distribution is often the hidden culprit behind failures that are otherwise difficult to trace.
Copper coins address the problem at its source. Because the coin sits directly beneath the component generating the heat, thermal energy never has to travel far through insulating material before reaching a conductive path out of the board.
Copper Coin PCB vs. Heavy Copper PCB
It's worth distinguishing a copper coin from a heavy copper PCB, since both address power and heat but solve different problems. Heavy copper construction increases copper thickness across entire layers or traces, typically 3 oz or more, to carry higher current and spread heat broadly across the board. A copper coin is a localized, high-mass insertion aimed at a specific hot spot rather than the whole layer.
Many high-power designs use both techniques together: heavy copper for overall current-carrying capacity and thermal spreading, paired with copper coins under the specific components generating concentrated heat, such as RF power amplifiers, MOSFETs, or metal-backed module hot spots.
When You Actually Need a Copper Coin
Copper coins aren't necessary on every board. They earn their added cost and complexity in specific situations:
High-power RF and microwave components, including power amplifiers and transmit modules, where localized heat can shift electrical characteristics and degrade signal performance.
Compact, high-density layouts where there isn't room for a large via farm or an external heat sink footprint.
Applications with a single dominant heat source, such as a MOSFET, LED driver, or power converter, rather than heat spread evenly across the board.
Designs are already pushing the limits of standard thermal vias and copper pours, where incremental improvements no longer move the needle.
If a board's heat load is distributed and moderate, standard vias, copper planes, or a heavy copper build may deliver adequate performance without the added manufacturing cost of coin insertion.
Design Considerations Before Specifying a Coin
Coin placement, shape, and installation method should be decided early in layout, not added after the fact. Key factors include the coefficient of thermal expansion (CTE) mismatch between copper and surrounding laminate, which can create mechanical stress during thermal cycling; the routing space consumed by the coin cavity; and whether an embedded or press-fit approach better matches production volume and tolerance requirements. ASC's thermal management design resources cover these tradeoffs in more depth, including guidance specific to RF and high-power digital applications.
About American Standard Circuits
American Standard Circuits (ASC) and Sunstone Circuits have joined forces to become a full-scale PCB solution provider with over 50 years of combined industry experience. ASC specializes in Ultra HDI, rigid, metal-backed and metal-core, RF/microwave, flex, and rigid-flex PCBs for military, aerospace, industrial, medical, and telecom customers, while Sunstone brings quick-turn production and hands-on customer support. Together, the companies support engineers from initial design through prototyping and full-scale production, backed by the kind of in-house thermal and materials expertise that specialty builds like copper coin PCBs require.
Bringing It Together
Embedded copper coins are a targeted, high-performance answer to a specific problem: getting heat out from under a hot component faster than vias or copper pours can manage alone. Used alongside broader thermal management PCB strategy, and weighed honestly against alternatives like heavy copper construction, they let engineers push power density further without sacrificing reliability. If you're evaluating thermal strategy for an RF, high-power, or metal-backed board, view ASC's technology capabilities or request a quote to talk through what your design actually needs.