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<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62508c236caf596192091e13/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">Hello and welcome to this presentati<span class="ls1 ws1">on on “External Thermal Resistance <span class="_ _0"></span>–</span></div><div class="t m0 x1 h2 y2 ff1 fs0 fc0 sc0 ls2 ws2">Substrates,” part of OSRAM Opto Se<span class="ls3 ws3">miconductors‘ LED Fundamentals series. </span></div><div class="t m0 x1 h2 y3 ff1 fs0 fc0 sc0 ls1 ws4">In this presentation <span class="ls4 ws5">we will look at the:</span></div><div class="t m0 x2 h2 y4 ff2 fs0 fc0 sc0 ls5 ws5"><span class="ff1 ls6 ws6">Thermal resistance of various substrate types.</span></div><div class="t m0 x2 h2 y5 ff2 fs0 fc0 sc0 ls5 ws5"><span class="ff1 ls7 ws7">Thermal management with pr<span class="ls8 ws8">inted circuit boards.</span></span></div><div class="t m0 x2 h2 y6 ff2 fs0 fc0 sc0 ls5 ws5"><span class="_ _1"> </span><span class="ff1 ls9 ws9">Examples that compare t<span class="wsa">he thermal <span class="_ _2"></span>resistance of </span></span></div><div class="t m0 x2 h2 y7 ff1 fs0 fc0 sc0 ls9 wsb">various substrate technologies. </div><div class="t m0 x3 h3 y8 ff1 fs1 fc0 sc0 ls5 ws5">1</div></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div>
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<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62508c236caf596192091e13/bg2.jpg"><div class="t m0 x1 h4 y1 ff1 fs0 fc0 sc0 ls1 ws4">The LED Fundamental module, <span class="_ _2"></span><span class="ff3 ls6 wsc">Internal Thermal Resistance of LEDs<span class="ff1 ls8 wsd">, discussed </span></span></div><div class="t m0 x1 h2 y2 ff1 fs0 fc0 sc0 ls8 wse">the internal thermal resistanc<span class="ls6 wsf">e of the LED package. In th<span class="_ _2"></span><span class="lsa ws10">is module we will continue </span></span></div><div class="t m0 x1 h2 y9 ff1 fs0 fc0 sc0 ls8 ws11">to discuss tracking the path of heat th<span class="ls3 ws12">rough an LED system and cover the thermal </span></div><div class="t m0 x1 h2 ya ff1 fs0 fc0 sc0 ls6 ws13">resistance offered by various substrates <span class="ls3 ws14">or printed circuit boards (PCBs) on which </span></div><div class="t m0 x1 h2 yb ff1 fs0 fc0 sc0 ls7 ws15">the LED component is <span class="_ _0"></span><span class="ls6 ws16">mounted in a <span class="_ _0"></span>system. </span></div><div class="t m0 x1 h2 yc ff1 fs0 fc0 sc0 ls6 ws17">Some of the more common types of PC<span class="lsb ws18">Bs used in an LED system design include </span></div><div class="t m0 x1 h2 yd ff1 fs0 fc0 sc0 ls0 ws19">FR4, metal core <span class="_ _2"></span>PCB and flex PCBs. In addi<span class="ls8 ws1a">tion <span class="_ _2"></span>to serving as an electrical contact, </span></div><div class="c x1 ye w2 h5"><div class="t m0 x0 h2 yf ff1 fs0 fc0 sc0 lsc ws5">P<span class="_ _3"></span>C<span class="_ _3"></span>B<span class="_ _4"> </span>l<span class="_ _4"> </span>h<span class="_ _5"> </span>t<span class="_ _6"> </span>f<span class="_ _3"></span>f<span class="_ _3"></span>i<span class="_ _7"> </span>i<span class="_ _8"> </span>td<span class="_ _3"></span>i<span class="_ _9"> </span>i<span class="_ _8"> </span>t<span class="_ _3"></span>i<span class="_ _a"> </span>ft<span class="_ _3"></span>h<span class="_"> </span>h<span class="_ _8"> </span>tt<span class="_ _3"></span>h<span class="_ _1"> </span>ti<span class="_ _b"> </span>t<span class="_ _1"> </span>d<span class="_ _9"> </span>i<span class="_ _3"></span>t<span class="_ _3"></span>h<span class="_ _3"></span>i</div></div><div class="c x1 y10 w2 h6"><div class="t m0 x0 h2 y11 ff1 fs0 fc0 sc0 lsd ws5">PCB</div></div><div class="t m0 x4 h2 y12 ff1 fs0 fc0 sc0 ls5 ws1b">s a</div><div class="c x1 y10 w2 h6"><div class="t m0 x5 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">l</div></div><div class="t m0 x6 h2 y12 ff1 fs0 fc0 sc0 ls7 ws5">so </div><div class="c x1 y10 w2 h6"><div class="t m0 x7 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">h</div></div><div class="t m0 x8 h2 y12 ff1 fs0 fc0 sc0 lse ws5">ave </div><div class="c x1 y10 w2 h6"><div class="t m0 x9 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">t</div></div><div class="t m0 xa h2 y12 ff1 fs0 fc0 sc0 ls0 ws1c">o ensure e</div><div class="c x1 y10 w2 h6"><div class="t m0 xb h2 y11 ff1 fs0 fc0 sc0 lsf ws5">ffi</div></div><div class="t m0 xc h2 y12 ff1 fs0 fc0 sc0 ls5 ws5">c</div><div class="c x1 y10 w2 h6"><div class="t m0 xd h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">i</div></div><div class="t m0 xe h2 y12 ff1 fs0 fc0 sc0 ls10 ws5">en</div><div class="c x1 y10 w2 h6"><div class="t m0 xf h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">t</div></div><div class="t m0 x10 h2 y12 ff1 fs0 fc0 sc0 ls5 ws5"> </div><div class="c x1 y10 w2 h6"><div class="t m0 x11 h2 y11 ff1 fs0 fc0 sc0 ls10 ws5">di</div></div><div class="t m0 x12 h2 y12 ff1 fs0 fc0 sc0 ls5 ws5">ss</div><div class="c x1 y10 w2 h6"><div class="t m0 x13 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">i</div></div><div class="t m0 x14 h2 y12 ff1 fs0 fc0 sc0 ls10 ws5">pa</div><div class="c x1 y10 w2 h6"><div class="t m0 x15 h2 y11 ff1 fs0 fc0 sc0 ls11 ws5">ti</div></div><div class="t m0 x16 h2 y12 ff1 fs0 fc0 sc0 ls10 ws1d">on o</div><div class="c x1 y10 w2 h6"><div class="t m0 x17 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">f</div></div><div class="t m0 x18 h2 y12 ff1 fs0 fc0 sc0 ls5 ws5"> </div><div class="c x1 y10 w2 h6"><div class="t m0 x19 h2 y11 ff1 fs0 fc0 sc0 ls11 ws5">th</div></div><div class="t m0 x1a h2 y12 ff1 fs0 fc0 sc0 ls10 ws5">e </div><div class="c x1 y10 w2 h6"><div class="t m0 x12 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">h</div></div><div class="t m0 x1b h2 y12 ff1 fs0 fc0 sc0 ls10 ws5">ea</div><div class="c x1 y10 w2 h6"><div class="t m0 x1c h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">t</div></div><div class="t m0 x1d h2 y12 ff1 fs0 fc0 sc0 ls5 ws5"> </div><div class="c x1 y10 w2 h6"><div class="t m0 x1e h2 y11 ff1 fs0 fc0 sc0 ls11 ws5">th</div></div><div class="t m0 x1f h2 y12 ff1 fs0 fc0 sc0 ls5 ws5">a</div><div class="c x1 y10 w2 h6"><div class="t m0 x20 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">t</div></div><div class="t m0 x21 h2 y12 ff1 fs0 fc0 sc0 ls5 ws5"> </div><div class="c x1 y10 w2 h6"><div class="t m0 x22 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">i</div></div><div class="t m0 x23 h2 y12 ff1 fs0 fc0 sc0 ls12 ws1e">s genera</div><div class="c x1 y10 w2 h6"><div class="t m0 x24 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">t</div></div><div class="t m0 x25 h2 y12 ff1 fs0 fc0 sc0 ls5 ws5">e</div><div class="c x1 y10 w2 h6"><div class="t m0 x26 h2 y11 ff1 fs0 fc0 sc0 ls5 ws5">d</div></div><div class="t m0 x27 h2 y12 ff1 fs0 fc0 sc0 lsf ws5"> w</div><div class="c x1 y10 w2 h6"><div class="t m0 x28 h2 y11 ff1 fs0 fc0 sc0 ls7 ws5">ithi</div></div><div class="t m0 x29 h2 y12 ff1 fs0 fc0 sc0 ls4 ws5">n </div><div class="t m0 x1 h2 y13 ff1 fs0 fc0 sc0 ls0 ws1f">the components, especially when working <span class="ws7">with high power components. The heat </span></div><div class="t m0 x1 h2 y14 ff1 fs0 fc0 sc0 lsb ws20">dissipation within a <span class="_ _0"></span>Printed Cir<span class="_ _0"></span><span class="ls8 ws21">cuit Board is either in-p<span class="ls0 ws22">lane (horizontal) or through </span></span></div><div class="t m0 x1 h2 y15 ff1 fs0 fc0 sc0 ls0 ws15">plane (vertical) or a combinat<span class="_ _0"></span><span class="lse ws23">ion of both. <span class="_ _2"></span>There are various<span class="ls12 ws24"> factors that influence the </span></span></div><div class="t m0 x1 h2 y16 ff1 fs0 fc0 sc0 ls0 ws25">heat conduction in printed ci<span class="ls3 ws12">rcuit boards and can be employed to reduce <span class="_ _2"></span>the thermal </span></div><div class="t m0 x1 h2 y17 ff1 fs0 fc0 sc0 ls8 ws8">resistance of the <span class="_ _0"></span>PCB. </div><div class="t m0 x3 h3 y8 ff1 fs1 fc0 sc0 ls5 ws5">2</div></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62508c236caf596192091e13/bg3.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls6 ws26">The value of the substrate thermal <span class="_ _2"></span>re<span class="ls1 ws27">sistance can be lowered by enlarging <span class="_ _2"></span>the </span></div><div class="t m0 x1 h2 y2 ff1 fs0 fc0 sc0 ls7 ws28">solder pad areas for the LED. <span class="_ _2"></span>The heat<span class="ws29"> propagates through <span class="_ _2"></span>the enlarged solder </span></div><div class="t m0 x1 h2 y9 ff1 fs0 fc0 sc0 ls1 ws2a">pads and is spread in the in-plane direction <span class="ls6 ws2b">of the PCB. Increas<span class="ls3 ws2c">ing the surface area </span></span></div><div class="t m0 x1 h2 ya ff1 fs0 fc0 sc0 ls7 ws29">of the solder pads is the simplest <span class="ws0">method to distribute heat on a PCB with no </span></div><div class="t m0 x1 h2 yb ff1 fs0 fc0 sc0 lse ws2d">additional <span class="_ _2"></span>cost. However<span class="_ _c"></span>, it is only possible <span class="_ _c"></span><span class="ls7 ws2e">to implement in desi<span class="ls3 ws2f">gns where there is a </span></span></div><div class="t m0 x1 h2 y18 ff1 fs0 fc0 sc0 ls9 ws30">low density of components. T<span class="lse ws31">he graph shows a decrease in <span class="ls6 ws32">thermal resistance of </span></span></div><div class="t m0 x1 h2 y19 ff1 fs0 fc0 sc0 ls8 ws33">the substrate for an increasing solder <span class="ls1 ws34">pad area for a TOPLED LED mounted on an </span></div><div class="c x1 ye w3 h7"><div class="t m0 x0 h2 y1a ff1 fs0 fc0 sc0 ls13 ws5">FR4<span class="_"> </span>PCB</div></div><div class="c x1 y1b w3 h8"><div class="t m0 x0 h2 y1c ff1 fs0 fc0 sc0 ls14 ws5">FR4</div></div><div class="t m0 x2a h2 y1d ff1 fs0 fc0 sc0 ls5 ws5"> </div><div class="c x1 y1b w3 h8"><div class="t m0 x2b h2 y1c ff1 fs0 fc0 sc0 lsd ws5">PCB</div></div><div class="t m0 x2c h2 y1d ff1 fs0 fc0 sc0 ls5 ws5">.</div><div class="t m0 x3 h3 y8 ff1 fs1 fc0 sc0 ls5 ws5">3</div></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div>
