Contents
When to use thermal relief PCB?
Thermal relief pads should be used whenever a thru-hole pin is connected to a fill of metal, a power plane, or any metal that is wider than the component pad. SMT parts soldered directly to large areas of metal should have some sort of thermal relief between their solder pad and the area of metal they are soldered to.
What is PCB thermal relief?
A thermal relief pad, thermal pad or simply thermal, is a printed circuit board (PCB) pad connected to a copper pour using a thermal connection. It looks like a normal pad with copper “spokes” connecting it to the surrounding copper. A typical pad on a printed circuit board is only connected to a few narrow tracks.
How does thermal management of a PCB work?
PCB thermal management techniques depend on a number of factors including the amount of heat the components and circuit dissipate, the environment, the overall design, and the enclosure. If heat generation is low, the circuit can work without additional cooling.
Why is it important to keep a PCB at a safe temperature?
Besides the components, the resistance of the electrical connections, copper traces, and vias contribute to some heat, and power losses. To avoid failures or circuit malfunctions, designers should aim at producing PCBs that operate and remain within safe temperature limits.
How to improve thermal dissipation ability of PCBs?
To improve thermal dissipation ability of PCBs, thickness of metal foil should be increased, and inner conductor should use metal foil with large area. What’s more, width of ground lines should be properly increased because ground lines with big area are both capable of increasing anti-interference ability and dissipating heat capacity.
Do you need thermal relief on ground connections?
A proper thermal relief on TH connections is a must for Lead free wave soldering. It is impossible to get 50% solder fill (or 47mil, which ever is less) on ground connections without thermal relief, especially on +90mil thick PCBs. There is IPC 2221A section 9.1.3, which has very good recommendation.