Bawo ni lati lo PCB for IC package heat dissipation?

The first aspect of PCB design that can improve thermal performance is the PCB device layout. Whenever possible, high-power components on the PCB should be separated from each other. This physical separation between high-power components maximizes the PCB area around each high-power component, thereby helping to achieve better heat conduction. Care should be taken to isolate temperature-sensitive components on the PCB from high-power components. Whenever possible, the installation location of high-power components should be far away from the corners of the PCB. A more central PCB location can maximize the board area around high-power components, thereby helping to dissipate heat. Figure 2 shows two identical semiconductor devices: component A and component B. Component A is located at the corner of the PCB and has a die junction temperature that is 5% higher than component B because component B is located closer to the middle. Since the board area around the component for heat dissipation is smaller, the heat dissipation at the corner of component A is limited.

How to use PCB for IC package heat dissipation?

The second aspect is the structure of the PCB, which has the most decisive influence on the thermal performance of the PCB design. The general principle is: the more copper in the PCB, the higher the thermal performance of the system components. The ideal heat dissipation situation for semiconductor devices is that the chip is mounted on a large piece of liquid-cooled copper. For most applications, this mounting method is impractical, so we can only make some other changes to the PCB to improve the heat dissipation performance. For most applications today, the total volume of the system continues to shrink, which has an adverse effect on heat dissipation performance. The larger the PCB, the larger the area that can be used for heat conduction, and it also has greater flexibility, allowing enough space between the high-power components.

Whenever possible, maximize the number and thickness of PCB copper ground planes. The weight of the ground layer copper is generally relatively large, and it is an excellent thermal path for the entire PCB to dissipate heat. The arrangement of wiring for each layer will also increase the total proportion of copper used for heat conduction. However, this wiring is usually electrically and thermally isolated, which limits its role as a potential heat dissipation layer. The wiring of the device ground plane should be as electrical as possible with many ground planes, so as to help maximize heat conduction. The heat dissipation vias on the PCB under the semiconductor device help heat to enter the buried layers of the PCB and conduct to the back of the circuit board.

To improve the heat dissipation performance, the top and bottom layers of the PCB are “golden locations”. Use wider wires and route them away from high-power devices to provide a thermal path for heat dissipation. The dedicated thermal board is an excellent method for PCB heat dissipation. The thermal board is generally located on the top or back of the PCB, and is thermally connected to the device through direct copper connections or thermal vias. In the case of inline package (packages with leads on both sides), this kind of heat conduction board can be located on the top of the PCB and shaped like a “dog bone” (the middle is as narrow as the package, and the area away from the package is relatively small. Large, small in the middle and large at the ends). In the case of a four-side package (there are leads on all four sides), the heat-conducting plate must be located on the back of the PCB or enter the PCB.

How to use PCB for IC package heat dissipation?

Alekun iwọn ti igbimọ igbona jẹ ọna ti o tayọ lati mu ilọsiwaju iṣẹ igbona ti package PowerPAD. Awọn iwọn awo idari ooru oriṣiriṣi ni ipa nla lori iṣẹ ṣiṣe igbona. Iwe data ọja ti a pese ni irisi tabili ni gbogbogbo ṣe atokọ alaye iwọn wọnyi. Sibẹsibẹ, o nira lati ṣe iwọn ipa ti bàbà ti a ṣafikun ti awọn PCB aṣa. Lilo diẹ ninu awọn oniṣiro ori ayelujara, awọn olumulo le yan ẹrọ kan lẹhinna yi iwọn paadi bàbà pada lati ṣe iṣiro ipa rẹ lori iṣẹ sisọnu ooru ti awọn PCB ti kii ṣe JEDEC. Awọn irinṣẹ iṣiro wọnyi ṣe afihan ipa ti apẹrẹ PCB lori iṣẹ ṣiṣe igbona. Fun package ẹgbẹ mẹrin, agbegbe ti paadi oke jẹ o kan kere ju agbegbe ti paadi ti o han ti ẹrọ naa. Ni idi eyi, awọn sin tabi ẹhin Layer jẹ ọna akọkọ lati ṣe aṣeyọri itutu agbaiye to dara julọ. Fun awọn idii laini meji, a le lo ara paadi “egungun aja” lati tu ooru kuro.

Nikẹhin, awọn ọna ṣiṣe pẹlu awọn PCB nla tun le ṣee lo fun itutu agbaiye. Ninu ọran ti awọn skru ti wa ni asopọ si awo ti n ṣe ooru ati ọkọ ofurufu ilẹ fun itusilẹ ooru, diẹ ninu awọn skru ti a lo lati gbe PCB le tun di awọn ọna igbona ti o munadoko si ipilẹ eto. Ṣiyesi ipa ipadabọ ooru ati idiyele, nọmba awọn skru yẹ ki o jẹ iye ti o pọju ti o de aaye ti idinku awọn ipadabọ. Lẹhin ti a ti sopọ si awo conductive gbona, irin PCB amuduro awo ni agbegbe itutu agbaiye diẹ sii. Fun diẹ ninu awọn ohun elo nibiti PCB ti bo pẹlu ikarahun kan, iru ohun elo atunṣe alurinmorin ti a ṣakoso ni iṣẹ ṣiṣe igbona ti o ga ju ikarahun tutu afẹfẹ. Awọn solusan itutu agbaiye, gẹgẹbi awọn onijakidijagan ati awọn ifọwọ ooru, tun jẹ awọn ọna ti o wọpọ fun itutu agbaiye eto, ṣugbọn wọn nigbagbogbo nilo aaye diẹ sii tabi nilo lati yi apẹrẹ naa pada lati mu ipa itutu dara dara.

Lati ṣe apẹrẹ eto pẹlu iṣẹ ṣiṣe igbona giga, ko to lati yan ẹrọ IC ti o dara ati ojutu pipade. Iṣẹ ṣiṣe ti ooru gbigbona ti IC da lori PCB ati agbara ti eto ifasilẹ ooru lati tutu awọn ẹrọ IC ni kiakia. Nipa lilo ọna itutu agbaiye palolo ti o wa loke, iṣẹ ṣiṣe itusilẹ ooru ti eto le ni ilọsiwaju pupọ.