Power Supply FR4 PCB – Heavy Copper & High Current

• Q1: How much current can a heavy copper PCB carry?

  A: Current capacity depends on copper weight, trace width, and acceptable temperature rise. As a guideline:

  • 2 oz copper: ~10A per 10mm width at 10°C rise

  • 4 oz copper: ~20A per 10mm width at 10°C rise

  • 6 oz copper: ~30A per 10mm width at 10°C rise

  For higher currents, we can combine multiple layers in parallel or use external bus bars. Contact us with your specific current requirements for a precise recommendation.

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  Q2: What is the minimum trace width for heavy copper PCBs?

  A: For signal traces on a heavy copper board, we can maintain 6 mil / 6 mil. For power traces, there is no minimum – we can make traces as wide as needed (up to the full board size). Wide power traces are actually preferred for minimizing resistance and heat.

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  Q3: Do I need high TG material for my power supply PCB?

  A: Highly recommended. Power supplies generate heat from switching MOSFETs, transformers, and rectifiers. Standard TG 130°C FR4 can soften and degrade over time under thermal stress. High TG 170°C FR4 maintains mechanical stability at higher temperatures, preventing via cracking and layer separation. We include high TG material as standard for all power supply PCBs at no additional cost.

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  Q4: Can you put heavy copper on inner layers as well as outer layers?

  A: Yes. We can provide heavy copper (2 oz to 6 oz) on both inner and outer layers. This is particularly useful for:

  • Inner layer power planes – distributing high current with low resistance

  • Outer layer traces – connecting to power components

  • Stackup symmetry – preventing warpage with balanced copper distribution

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  Q5: What is the typical turnaround time for heavy copper PCBs?

  A: Heavy copper requires additional processing time (plating cycles, etching adjustments). Typical lead times:

  • Prototype quantities (1-20 pieces): 7-10 working days

  • Mass production (above 50 pieces): 12-15 working days

  This is approximately 2-3 days longer than standard 1 oz copper PCBs.

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  Q6: What surface finish do you recommend for power supply PCBs?

  A: Lead-Free HASL is the most common and cost-effective choice for power supplies. It provides good solderability for large power components (TO-220, TO-247, screw terminals, transformers). ENIG is preferred if you have fine-pitch ICs on the same board (e.g., power management ICs, controllers). OSP is not recommended for power supplies.

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  Q7: Can you make very thick PCBs for heavy components?

  A: Yes. We can manufacture up to 2.4mm (0.093″) thick FR4 PCBs. This thickness provides:

  • Mechanical rigidity for heavy transformers and inductors

  • Support for large screw terminal connectors

  • Reduced warpage during assembly and operation

  For extremely heavy components, we can also discuss mounting hole reinforcement or metal brackets.

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  Q8: Do you provide thermal via arrays for power components?

  A: Yes. Thermal vias are essential for conducting heat away from surface-mount power components (MOSFETs, voltage regulators, LEDs). We can provide:

  • Dense via arrays under thermal pads (e.g., 0.3mm vias on 0.6mm grid)

  • Via-in-pad with filling (for better thermal transfer)

  • Connection to internal ground/power planes that act as heat spreaders

  Specify your thermal via requirements in your design files or notes.

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  Q9: How does heavy copper affect PCB cost?

  A: Heavy copper increases cost due to:

  • Longer plating times

  • More expensive copper foil and materials

  • Additional etching and processing steps

  • Slower production throughput

  Typical cost increase:

  • 2 oz copper: +30-40% vs 1 oz

  • 3 oz copper: +50-70% vs 1 oz

  • 4 oz copper: +70-100% vs 1 oz

  • 6 oz copper: Custom quote required

  For many power supply applications, the reliability improvement and board space savings justify the additional cost.

Shipping Terms

Shipping costs are paid by the buyer.
We normally ship via DHL, UPS, FedEx, or TNT.
Alternatively, you may provide your own courier account or arrange delivery to your freight forwarder in China.

For large-volume orders, sea freight is available.

Delivery to Port (FOB Terms)

When shipping to a port, Tengxinjie is responsible for transporting the goods to the departure port.
All customs clearance, ocean freight, insurance, and onward transportation after that point are the responsibility of the buyer.

Tengxinjie can recommend reliable local freight forwarders upon request.
With the buyer’s authorization, Tengxinjie may also assist in coordinating shipping, with all related costs charged to the buyer.

Notice

The above shipping information is for reference only.
Tracking details and shipment updates will be provided once the order has been dispatched.

PCBA Shipping Delivery