VIAS IN SPRINT LAYOUT TRIAL

The best thing is to fill the vias, which really gets the heat out, but is an extra-cost option. Note the thicker copper on the top and bottom helps to dissipate the heat, and the bigger the area, the better. Here is a nice side-view of some thermal vias in a PCB. The first problem is that the amount of copper in the вЂњbarrelвЂќ is dependent on the circuit board fabricator. One is that vias rarely work as well as you need them to. So I and several pals have learned a few things with real-world experience.

VIAS IN SPRINT LAYOUT TRIAL

You have to rely on my brotherвЂ™s maxim from Bell Labs: вЂњAn ounce of trial is worth a pound of opinion.вЂќ And any simulation is just that, a computerвЂ™s opinion on what your circuit will do. After all, a diode has 0.6 to 0.9 volts across it, while a modern FET has such low on-resistance it hardly drops any voltage at all.Д«ut realize a simulation is just that, for both electrical and thermal designs. It made perfect sense once I saw the heat diagram. This is what taught me that a modern buck regulator will have more heat coming out of the catch diode than the pass FET. Texas Instruments WEBENCH is a neat program, especially because it has Mentor GraphicвЂ™s FloTherm built in to help you see the hot spots in switching regulators. Note the buck regulator catch diode is the hottest thing on the board, and how little heat is radiated out the bottom, despite the thermal vias. WEBENCH can estimate thermal performance of a switching regulator, but it is just an estimate, highly dependent on your particular layout and application.

Same goes if you have the board covered with some tight enclosure. If you have a lot of hot components you canвЂ™t expect the same die temperatures for the part in question. You have to realize the guidelines in the datasheet are usually based on one part making heat, sitting on a standard board of a certain dimensions. No there is a lot of caution you need to exercise when trying to get the heat out of a part just using a circuit board. The use of thermally conductive planes to spread the heat evenly dramatically lowers the temperature by maximizing the area used for heat transfer to the atmosphere (Fig. Establishing effective heat and high-current routes will optimize heat transfer by means of convection. вЂњTo reduce operating temperatures easily, use more layers of solid ground or power planes connected directly to heat sources with multiple vias. The article talks about using vias to take heat away from the die-attach-paddle (DAP) of integrated circuits: ItвЂ™s a pretty good article and I am glad to see the trade magazines realize we care as much about PCB layout as the bus-caching architecture of some DSP chip. I came across an article on PCB layout in Electronic Design magazine.

Vias in sprint layout