{"id":4641,"date":"2026-01-19T09:23:39","date_gmt":"2026-01-19T09:23:39","guid":{"rendered":"https:\/\/flj-pcb.com\/?p=4641"},"modified":"2026-01-19T09:23:44","modified_gmt":"2026-01-19T09:23:44","slug":"fr-4-pcb-guide-properties-limits-material-choices","status":"publish","type":"post","link":"https:\/\/flj-pcb.com\/cs\/fr-4-pcb-guide-properties-limits-material-choices\/","title":{"rendered":"Pr\u016fvodce deskami plo\u0161n\u00fdch spoj\u016f FR-4: Vlastnosti, limity a volba materi\u00e1lu"},"content":{"rendered":"<h2 class=\"wp-block-heading\">fr4 - definice a v\u00fdznam<\/h2>\n\n\n\n<p>fr4 je k\u00f3d pro t\u0159\u00eddu neho\u0159lavosti epoxidov\u00e9ho lamin\u00e1tu vyztu\u017een\u00e9ho skeln\u00fdmi vl\u00e1kny s m\u011bd\u011bn\u00fdm pl\u00e1\u0161t\u011bm. Znamen\u00e1 to, \u017ee prysky\u0159ice mus\u00ed po zap\u00e1len\u00ed p\u0159estat sama ho\u0159et. fr4 nen\u00ed n\u00e1zev jednoho konkr\u00e9tn\u00edho materi\u00e1lu. Je to t\u0159\u00edda materi\u00e1lu pou\u017e\u00edvan\u00e1 pro desky plo\u0161n\u00fdch spoj\u016f (PCB).<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">slo\u017een\u00ed a b\u011b\u017en\u00e9 typy<\/h2>\n\n\n\n<p>V b\u011b\u017en\u00fdch desk\u00e1ch plo\u0161n\u00fdch spoj\u016f se pou\u017e\u00edv\u00e1 mnoho druh\u016f materi\u00e1l\u016f fr4. V\u011bt\u0161inou se jedn\u00e1 o kompozitn\u00ed materi\u00e1ly vyroben\u00e9 z takzvan\u00e9 tetrafunk\u010dn\u00ed epoxidov\u00e9 prysky\u0159ice, plniv a sklen\u011bn\u00fdch vl\u00e1ken.<\/p>\n\n\n\n<p>P\u0159\u00edklad: pokud specifikace PCB zn\u00ed <strong>fr4 T:1.0 D\/S<\/strong>, to znamen\u00e1: fr4 stupe\u0148 neho\u0159lavosti, T:1,0 znamen\u00e1 tlou\u0161\u0165ku 1,0 mm, D\/S znamen\u00e1 oboustrann\u00fd. Jin\u00fdmi slovy, materi\u00e1l desky je epoxidov\u00e1 skeln\u00e1 tkanina, oboustrann\u00fd lamin\u00e1t s m\u011bd\u011bn\u00fdm pl\u00e1\u0161t\u011bm, tlou\u0161\u0165ka 1 mm, oboustrann\u00fd.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">fr4 - kl\u00ed\u010dov\u00e9 vlastnosti a klasifikace<\/h2>\n\n\n\n<p>Z technick\u00e9ho hlediska maj\u00ed lamin\u00e1ty fr4 \u0159adu kl\u00ed\u010dov\u00fdch specifikac\u00ed. Mezi n\u011b pat\u0159\u00ed:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>pevnost v ohybu a pevnost v odlupov\u00e1n\u00ed a odolnost proti tepeln\u00fdm \u0161ok\u016fm;<\/li>\n\n\n\n<li>siln\u00e1 odolnost proti \u0161\u00ed\u0159en\u00ed plamene;<\/li>\n\n\n\n<li>objemov\u00fd odpor a povrchov\u00fd odpor;<\/li>\n\n\n\n<li>dielektrick\u00e1 konstanta (Dk) a rozptylov\u00fd faktor (tangens ztr\u00e1t);<\/li>\n\n\n\n<li>teplota skeln\u00e9ho p\u0159echodu (Tg);<\/li>\n\n\n\n<li>rozm\u011brov\u00e1 stabilita, maxim\u00e1ln\u00ed teplota pou\u017eit\u00ed a deformace.<\/li>\n<\/ul>\n\n\n\n<p>Tyto vlastnosti spole\u010dn\u011b definuj\u00ed v\u00fdkonnost fr4 p\u0159i v\u00fdrob\u011b DPS.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">dal\u0161\u00ed b\u011b\u017en\u00e9 z\u00e1kladn\u00ed materi\u00e1ly PCB<\/h2>\n\n\n\n<p>\u25c9 desky na b\u00e1zi sklen\u011bn\u00e9 tkaniny<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Desky ze sklen\u011bn\u00e9 tkaniny: fr4 a fr5<br>V obou p\u0159\u00edpadech se pou\u017e\u00edv\u00e1 speci\u00e1ln\u00ed elektronick\u00e1 tkanina napu\u0161t\u011bn\u00e1 epoxidovou (nebo epoxid-fenolickou) prysky\u0159ic\u00ed. Pot\u00e9 se vytvrzuj\u00ed za vysok\u00e9ho tepla a tlaku. fr4 je nejpou\u017e\u00edvan\u011bj\u0161\u00ed deska p\u0159i v\u00fdrob\u011b DPS. M\u00e1 dobr\u00e9 elektrick\u00e9 vlastnosti, dobrou mechanickou pevnost a tepelnou odolnost. \u0160iroce se pou\u017e\u00edv\u00e1 p\u0159i v\u00fdrob\u011b v\u00edcevrstv\u00fdch desek plo\u0161n\u00fdch spoj\u016f.<\/li>\n<\/ol>\n\n\n\n<p>\u25c9 Desky na b\u00e1zi pap\u00edru<br>2. Pap\u00edrov\u00e9 desky: fr-1, fr-2, fr-3<br>Fenolick\u00e9 pap\u00edrov\u00e9 desky pou\u017e\u00edvaj\u00ed jako pojivo fenolickou prysky\u0159ici a jako povrchovou v\u00fdztu\u017e d\u0159evovl\u00e1knitou tkaninu. Vyr\u00e1b\u011bj\u00ed se za vysok\u00e9ho tepla a tlaku.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"450\" src=\"https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/Paper-based-boards.webp\" alt=\"Paper based boards\" class=\"wp-image-4642\" srcset=\"https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/Paper-based-boards.webp 800w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/Paper-based-boards-300x169.webp 300w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/Paper-based-boards-768x432.webp 768w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/Paper-based-boards-18x10.webp 18w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/><\/figure>\n\n\n\n<p>\u25c9 Kompozitn\u00ed desky<br>3. Kompozitn\u00ed desky: CEM-1 a CEM-3<br>Mezi kompozitn\u00ed desky pat\u0159\u00ed \u0159ada m\u011bd\u00ed pl\u00e1tovan\u00fdch lamin\u00e1t\u016f CEM. CEM-1 pou\u017e\u00edv\u00e1 jako j\u00e1dro epoxidov\u00fd pap\u00edr. CEM-3 pou\u017e\u00edv\u00e1 jako j\u00e1dro epoxidovou sklen\u011bnou netkanou textilii. Tyto desky CEM se snadno zpracov\u00e1vaj\u00ed. Maj\u00ed dobrou rovinnost, rozm\u011brovou stabilitu a p\u0159esnou tlou\u0161\u0165ku. Jejich mechanick\u00e1 pevnost, dielektrick\u00e9 vlastnosti, absorpce vody a odolnost proti migraci kov\u016f jsou lep\u0161\u00ed ne\u017e u pap\u00edrov\u00fdch desek. Zejm\u00e9na desky CEM-3 mohou dosahovat p\u0159ibli\u017en\u011b 80% mechanick\u00e9 pevnosti desek fr4, ale obvykle stoj\u00ed m\u00e9n\u011b.<\/p>\n\n\n\n<p>\u25c9 Speci\u00e1ln\u00ed materi\u00e1lov\u00e9 desky<br>4. Speci\u00e1ln\u00ed desky (nap\u0159, <a href=\"https:\/\/flj-pcb.com\/cs\/pcb-manufacturer\/ceramic-pcb\/\" data-type=\"page\" data-id=\"2364\">keramika a kov<\/a>)<br>Pat\u0159\u00ed mezi n\u011b keramick\u00e9 substr\u00e1ty a desky s kovov\u00fdm j\u00e1drem. Maj\u00ed speci\u00e1ln\u00ed vlastnosti pro aplikace, kter\u00e9 vy\u017eaduj\u00ed vy\u0161\u0161\u00ed v\u00fdkon materi\u00e1lu.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"500\" height=\"469\" src=\"https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/ceramic-pcb.webp\" alt=\"ceramic pcb\" class=\"wp-image-4643\" srcset=\"https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/ceramic-pcb.webp 500w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/ceramic-pcb-300x281.webp 300w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/ceramic-pcb-13x12.webp 13w\" sizes=\"(max-width: 500px) 100vw, 500px\" \/><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">v\u00fdhody a omezen\u00ed fr4<\/h2>\n\n\n\n<p>Od doby, kdy jsem za\u010dal navrhovat desky plo\u0161n\u00fdch spoj\u016f, je fr4 standardn\u00edm materi\u00e1lem desek. Zpo\u010d\u00e1tku n\u011bkte\u0159\u00ed n\u00e1vrh\u00e1\u0159i naz\u00fdvali ka\u017edou desku \u201cfr4\u201d, a\u0165 u\u017e to tak bylo, nebo ne. fr4 je neho\u0159lav\u00fd epoxidov\u00fd lamin\u00e1t typu 4 vyztu\u017een\u00fd sklen\u011bn\u00fdmi vl\u00e1kny. Je cenov\u011b v\u00fdhodn\u00fd. Je dobr\u00fdm elektrick\u00fdm izolantem. Je pevn\u00fd v such\u00fdch i vlhk\u00fdch podm\u00ednk\u00e1ch. Snadno se tak\u00e9 vyr\u00e1b\u00ed do desek. Z t\u011bchto d\u016fvod\u016f je fr4 b\u011b\u017enou volbou pro v\u00fdrobu desek plo\u0161n\u00fdch spoj\u016f.<\/p>\n\n\n\n<p>fr4 m\u00e1 sv\u00e9 limity. M\u016f\u017ee se dostat do probl\u00e9m\u016f, kdy\u017e je p\u0159\u00edli\u0161 velk\u00fd v\u00fdkon, nap\u011bt\u00ed nebo teplo. Pokud ho budete tla\u010dit za jeho hranice, jeho dielektrick\u00e9 vlastnosti se sn\u00ed\u017e\u00ed. To znamen\u00e1, \u017ee materi\u00e1l ztrat\u00ed izolaci a za\u010dne vodit. Dal\u0161\u00edm probl\u00e9mem je udr\u017een\u00ed stabiln\u00ed impedance ve vysokorychlostn\u00edch konstrukc\u00edch. dielektrick\u00e1 konstanta fr4 se m\u016f\u017ee m\u011bnit v z\u00e1vislosti na d\u00e9lce a \u0161\u00ed\u0159ce desky. Se zvy\u0161uj\u00edc\u00ed se konstruk\u010dn\u00ed rychlost\u00ed m\u016f\u017ee b\u00fdt ztr\u00e1ta sign\u00e1lu, kter\u00e1 byla p\u0159ijateln\u00e1 u desek s n\u00edzkou rychlost\u00ed, u desek fr4 p\u0159\u00edli\u0161 vysok\u00e1.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">je fr4 nejlep\u0161\u00ed volbou pro vysokorychlostn\u00ed n\u00e1vrh DPS?<\/h2>\n\n\n\n<p>Kdy\u017e se pust\u00edme do projektu mimo svou komfortn\u00ed z\u00f3nu, pozn\u00e1me nov\u00e9 hranice. Pro m\u011b ten den nastal, kdy\u017e m\u011b \u0161\u00e9f po\u017e\u00e1dal o <a href=\"https:\/\/flj-pcb.com\/cs\/pcb-manufacturer\/high-speed-pcb\/\" data-type=\"page\" data-id=\"2370\">vysokorychlostn\u00ed deska<\/a>. V\u011bd\u011bl jsem, \u017ee vysokorychlostn\u00ed konstrukce p\u0159in\u00e1\u0161\u00ed limity, kter\u00e9 v b\u011b\u017en\u00fdch obvodech nevid\u00edme. Nejprve jsem vytvo\u0159il sch\u00e9ma vhodn\u00e9 pro vysokou rychlost. Pak jsem se zam\u011b\u0159il na to, zda by m\u011bl vysokorychlostn\u00ed prototyp pou\u017e\u00edvat fr4 nebo specializovan\u011bj\u0161\u00ed materi\u00e1l. Ne\u017e se rozhodnete, uv\u011bdomte si, \u017ee v tomto textu se v\u00fdraz \u201cvysokorychlostn\u00ed\u201d pou\u017e\u00edv\u00e1 pro cokoli nad \u00farovn\u00ed <strong>50 MHz<\/strong>. To jsou podstatn\u00e9 probl\u00e9my v tomto frekven\u010dn\u00edm rozsahu.<\/p>\n\n\n\n<p>Vysokorychlostn\u00ed konstrukce maj\u00ed p\u0159\u00edsn\u011bj\u0161\u00ed pravidla pro integritu sign\u00e1lu. Abyste tato pravidla splnili, mus\u00edte pe\u010dliv\u011b kontrolovat sm\u011brov\u00e1n\u00ed. Sou\u010d\u00e1st\u00ed rovnice integrity sign\u00e1lu je v\u0161ak i samotn\u00fd materi\u00e1l desky. Materi\u00e1l pro vysokorychlostn\u00ed desky by tedy m\u011bl m\u00edt p\u0159\u00edsnou toleranci Dk a dal\u0161\u00ed kontrolovan\u00e9 vlastnosti, kter\u00e9 pom\u00e1haj\u00ed \u0159\u00eddit impedanci. Pokud se impedance nap\u0159\u00ed\u010d konstrukc\u00ed m\u011bn\u00ed, vysokorychlostn\u00ed sign\u00e1ly budou p\u0159i sv\u00e9m pohybu odr\u00e1\u017eet energii zp\u011bt a sign\u00e1l se zkresl\u00ed. Tak\u00e9 n\u00edzk\u00fd ztr\u00e1tov\u00fd tangens pom\u00e1h\u00e1 udr\u017eet sign\u00e1l siln\u00fd. A kone\u010dn\u011b, tepeln\u00e1 stabilita pom\u00e1h\u00e1 zajistit, aby se dielektrick\u00e9 vlastnosti neporu\u0161ily.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">jak se specializovan\u00e9 vysokorychlostn\u00ed materi\u00e1ly srovn\u00e1vaj\u00ed s fr4<\/h2>\n\n\n\n<p>Speci\u00e1ln\u00ed vysokorychlostn\u00ed materi\u00e1ly, jako jsou termosetov\u00e9 uhlovod\u00edkov\u00e9 lamin\u00e1ty a teflonov\u00e9 lamin\u00e1ty, \u010dasto poskytuj\u00ed lep\u0161\u00ed a spolehliv\u011bj\u0161\u00ed v\u00fdkon v konstrukc\u00edch s vy\u0161\u0161\u00ed frekvenc\u00ed ne\u017e fr4. N\u00ed\u017ee jsou uvedeny n\u011bkter\u00e9 kl\u00ed\u010dov\u00e9 v\u00fdhody t\u011bchto materi\u00e1l\u016f:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" width=\"700\" height=\"525\" src=\"https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/high-speed-pcb.webp\" alt=\"high-speed pcb\" class=\"wp-image-4645\" srcset=\"https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/high-speed-pcb.webp 700w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/high-speed-pcb-300x225.webp 300w, https:\/\/flj-pcb.com\/wp-content\/uploads\/2026\/01\/high-speed-pcb-16x12.webp 16w\" sizes=\"(max-width: 700px) 100vw, 700px\" \/><\/figure>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Sn\u00ed\u017een\u00ed ztr\u00e1ty sign\u00e1lu.<\/strong> S rostouc\u00ed frekvenc\u00ed p\u0159enosov\u00e9ho veden\u00ed roste ztr\u00e1ta sign\u00e1lu. Vysokorychlostn\u00ed lamin\u00e1ty maj\u00ed mnohem ni\u017e\u0161\u00ed ztr\u00e1tov\u00fd tangens ne\u017e fr4. N\u011bkter\u00e9 materi\u00e1ly, nap\u0159\u00edklad lamin\u00e1ty z t\u00e9m\u011b\u0159 \u010dist\u00e9ho PTFE, jsou \u0159\u00e1dov\u011b lep\u0161\u00ed. Ni\u017e\u0161\u00ed tangens ztr\u00e1t je kl\u00ed\u010dov\u00fdm faktorem pro sn\u00ed\u017een\u00ed ztr\u00e1t sign\u00e1lu.<\/li>\n\n\n\n<li><strong>P\u0159\u00edsn\u011bj\u0161\u00ed kontrola impedance.<\/strong> Tradi\u010dn\u00ed materi\u00e1ly, jako je fr4, nedok\u00e1\u017eou dr\u017eet dielektrickou konstantu (Dk) tak pevn\u011b jako vysokorychlostn\u00ed materi\u00e1ly. fr4 Dk se m\u016f\u017ee li\u0161it o \u00b110% nebo v\u00edce. Materi\u00e1ly jako PTFE mohou udr\u017eet Dk v rozmez\u00ed \u00b12% nebo lep\u0161\u00edm.<\/li>\n\n\n\n<li><strong>Lep\u0161\u00ed tepeln\u00e1 spr\u00e1va.<\/strong> N\u011bkter\u00e9 vysokorychlostn\u00ed lamin\u00e1ty (nap\u0159. termosetov\u00e9 uhlovod\u00edkov\u00e9 lamin\u00e1ty) maj\u00ed mnohem lep\u0161\u00ed tepelnou vodivost ne\u017e fr4. Pokud va\u0161e konstrukce pot\u0159ebuje \u0159\u00eddit teplo, stoj\u00ed za to tyto lamin\u00e1ty prostudovat.<\/li>\n\n\n\n<li><strong>Ni\u017e\u0161\u00ed p\u0159\u00edjem vlhkosti.<\/strong> Voda m\u00e1 dielektrick\u00e9 \u00fa\u010dinky. I mal\u00e1 vlhkost v desce plo\u0161n\u00fdch spoj\u016f m\u016f\u017ee zm\u011bnit elektrick\u00fd v\u00fdkon vysokofrekven\u010dn\u00edch obvod\u016f. A\u010dkoli text uv\u00e1d\u00ed, \u017ee absorpce vlhkosti fr4 je t\u00e9m\u011b\u0159 50%, n\u011bkter\u00e9 vysokorychlostn\u00ed materi\u00e1ly (nap\u0159\u00edklad n\u011bkter\u00e9 lamin\u00e1ty PTFE) mohou m\u00edt mnohem ni\u017e\u0161\u00ed absorpci vlhkosti, t\u00e9m\u011b\u0159 2%, a to pom\u00e1h\u00e1 udr\u017eet stabiln\u00ed elektrick\u00e9 chov\u00e1n\u00ed.<\/li>\n\n\n\n<li><strong>V\u011bt\u0161\u00ed rozm\u011brov\u00e1 stabilita.<\/strong> Hust\u00e9 vysokorychlostn\u00ed uspo\u0159\u00e1d\u00e1n\u00ed vy\u017eaduje p\u0159\u00edsnou kontrolu rozm\u011br\u016f. fr4 je zn\u00e1m\u00fd dobrou rozm\u011brovou stabilitou, ale n\u011bkter\u00e9 vysokorychlostn\u00ed materi\u00e1ly nab\u00edzej\u00ed lep\u0161\u00ed celkov\u00fd v\u00fdkon pro konstrukce s p\u0159\u00edsnou toleranc\u00ed. V takov\u00fdch p\u0159\u00edpadech mohou b\u00fdt lep\u0161\u00ed volbou termosetov\u00e9 uhlovod\u00edkov\u00e9 lamin\u00e1ty.<\/li>\n<\/ol>","protected":false},"excerpt":{"rendered":"<p>fr4 \u2014 definition and meaning fr4 is the code for the flame-retardant rating of a glass-fiber reinforced epoxy copper clad [&hellip;]<\/p>","protected":false},"author":1,"featured_media":4644,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center 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