Txhawm rau kom ntseeg tau tias cov teeb liab kis tau zoo, txo qis EMI cuam tshuam, thiab dhau qhov cuam tshuam cuam tshuam kev xeem ntawv pov thawj, PCB tseem ceeb teeb liab impedance txuam tsim yog yuav tsum tau. Daim ntawv qhia kev tsim qauv no yog ua raws li cov lus qhia tsis sib xws, TV khoom teeb liab cov yam ntxwv, PCB Layout yuav tsum, SI9000 software xam, PCB cov ntaub ntawv tawm tswv yim thiab lwm yam, thiab thaum kawg tuaj rau qhov kev pom zoo tsim. Haum rau feem ntau PCB cov neeg muag khoom ‘cov txheej txheem txheej txheem thiab PCB board tsim nrog impedance tswj cov cai.

Ib. Ob chav vaj huam sib luag impedance tsim

① Kev tsim hauv av: kab dav, sib nrug 7/5/7mil av hlau dav ≥20mil teeb liab thiab av xaim nrug 6mil, txhua 400mil hauv av qhov; (2) Non-enveloping design: kab dav, qhov sib nrug ntawm 10/5/10mil sib txawv khub thiab qhov kev ncua deb ntawm khub ≥20mil (qhov xwm txheej tshwj xeeb tsis tuaj yeem tsawg dua 10mil) nws raug pom zoo tias tag nrho cov pab pawg sib txawv ntawm cov kab sib txawv siv lub hnab ntawv shielding, sib txawv teeb liab thiab shielding hauv av nyob deb ≥35mil (tshwj xeeb tsis tuaj yeem tsawg dua 20mil). 90 ohm txawv impedance pom zoo tsim

Kab dav, sib nrug 10/5/10mil Av hlau dav ≥20mil Teeb liab thiab av xaim deb ntawm 6mil lossis 5mil, grounding qhov txhua 400mil; ②Tsis suav nrog tus tsim:

Kab dav thiab qhov sib nrug 16/5/16mil qhov kev ncua deb ntawm qhov sib txawv teeb liab khub ≥20mil nws raug pom zoo kom siv cov hnab ntawv hauv av rau tag nrho cov pab pawg ntawm cov teeb liab sib txawv. Qhov kev ncua deb ntawm lub teeb liab sib txawv thiab cov ntaub thaiv npog hauv av yuav tsum yog ≥35mil (lossis ≥20mil hauv qhov tshwj xeeb). Cov ntsiab lus tseem ceeb: muab qhov tseem ceeb rau kev siv cov qauv hauv av npog, kab luv luv thiab ua tiav lub dav hlau tuaj yeem siv yam tsis muaj kev tsim hauv av; Kev suav tsis suav: Phaj FR-4, phaj thickness 1.6mm +/-10%, phaj dielectric tas li 4.4+/-0.2, tooj liab thickness 1.0 oz (1.4mil) solder roj thickness 0.6±0.2mil, dielectric tas li 3.5+/-0.3.

Impedance tsim ntawm ob thiab plaub txheej

100 ohm sib txawv impedance pom zoo tsim kab dav thiab qhov sib nrug 5/7/5mil qhov kev ncua deb ntawm khub ≥14mil (3W kev ntsuas) ceeb toom: nws raug pom zoo kom siv cov ntaub ntawv hauv av rau tag nrho cov pab pawg ntawm cov teeb liab sib txawv. Qhov kev ncua deb ntawm qhov sib txawv ntawm cov teeb liab thiab cov shielding av cable yuav tsum yog tsawg kawg yog 35mil (tsis tsawg tshaj li 20mil nyob rau hauv tshwj xeeb mob). 90ohm sib txawv impedance Pom zoo tsim kab dav thiab qhov sib txawv 6/6/6mil Differential khub nrug ≥12mil (3W kev ntsuas) Cov ntsiab lus tseem ceeb: Nyob rau hauv rooj plaub ntawm qhov sib txawv ntev ntawm lub cable, nws raug pom zoo tias qhov kev ncua deb ntawm ob sab ntawm USB sib txawv kab qhwv hauv av los ntawm 6mil kom txo tau EMI kev pheej hmoo (pob hauv av thiab tsis qhwv hauv av, kab dav thiab kab nrug tus qauv zoo ib yam). Muab xam parameters: Fr-4, phaj thickness 1.6mm +/-10%, phaj dielectric tas li 4.4+/-0.2, Copper thickness 1.0oz (1.4mil) semi-kho ntawv (PP) 2116 (4.0-5.0mil), dielectric tas li 4.3+/ -0.2 solder roj thickness 0.6 ± 0.2mil, Dielectric tas li 3.5+/-0.3 laminated qauv: tshuaj ntsuam luam ntawv txheej solder txheej tooj liab txheej semi-kho zaj duab xis coated tooj liab substrate semi-kho zaj duab xis tooj liab txheej solder txheej npo luam ntawv txheej

Peb. Rau txheej board impedance tsim

Cov txheej txheem rau-txheej lamination yog txawv rau ntau zaus. Cov lus qhia no tsuas yog pom zoo rau kev tsim cov lamination ntau dua (saib daim duab 2), thiab cov qauv hauv qab no tau pom zoo raws li cov ntaub ntawv tau txais hauv lamination hauv FIG. 2. Lub impedance tsim ntawm txheej txheej yog tib yam li ntawm plaub-txheej board. Vim tias cov txheej txheem sab hauv feem ntau muaj cov txheej txheem dav hlau ntau dua li cov txheej txheem saum npoo, qhov chaw electromagnetic txawv ntawm txheej txheej. Cov hauv qab no yog cov lus qhia rau kev tiv thaiv impedance ntawm peb txheej thaiv (laminated siv daim duab 4). 90 ohm txawv impedance Pom zoo tsim kab dav, kab nrug 8/10/8mil Qhov sib txawv khub nrug ≥20mil (3W kev ntsuas); Muab xam parameters: Fr-4, phaj thickness 1.6mm +/-10%, phaj dielectric tas li 4.4+/-0.2, Copper thickness 1.0oz (1.4mil) semi-kho ntawv (PP) 2116 (4.0-5.0mil), dielectric tas li 4.3+/ -0.2 solder roj thickness 0.6 ± 0.2mil, Dielectric tas li 3.5+/-0.3 laminated qauv: sab saum toj screen thaiv txheej tooj liab txheej semi-kho tooj liab-coated substrate semi-kho tooj liab-coated substrate semi-kho tooj liab-coated txheej hauv qab npo thaiv txheej

Rau ntau tshaj plaub lossis rau txheej, thov tsim los ntawm koj tus kheej raws li cov kev cai cuam tshuam lossis sab laj nrog cov neeg ua haujlwm los txiav txim siab cov qauv lamination thiab cov txheej txheem xaim.

5. Yog tias muaj lwm yam kev tswj hwm impedance vim muaj xwm txheej tshwj xeeb, thov xam los ntawm koj tus kheej lossis sab laj nrog cov neeg ua haujlwm cuam tshuam los txiav txim cov qauv tsim.

Lus Cim: ① Muaj ntau qhov xwm txheej uas cuam tshuam rau impedance. Yog hais tias PCB yuav tsum tau tswj los ntawm impedance, cov kev cai ntawm impedance tswj yuav tsum tau cim kom meej nyob rau hauv lub PCB tsim cov ntaub ntawv los yog cov qauv ntawv; (2) 100 ohm txawv impedance yog tsuas yog siv rau HDMI thiab LVDS cov cim qhia, uas HDMI xav tau kom dhau cov ntawv pov thawj cuam tshuam yog qhov yuav tsum tau ua; ③ 90 ohm txawv impedance yog siv rau USB teeb liab; (4) Ib lub davhlau ya nyob twg 50 ohm impedance feem ntau yog siv rau ib feem ntawm DDR teeb liab. Txij li feem ntau DDR hais tau txais kev hloov kho sab hauv txuam nrog impedance tsim, tus qauv tsim yog raws li Demo board muab los ntawm lub tuam txhab kev daws teeb meem raws li kev siv, thiab cov qauv tsim no tsis pom zoo. ⑤, ib leeg-kawg 75-ohm impedance yog tsuas yog siv rau analog video input thiab tso zis. Muaj 75-ohm tsis kam sib piv cov av tiv thaiv ntawm kev tsim hluav taws xob, yog li nws tsis tsim nyog los ua cov impedance txuam tsim hauv PCB Layout, tab sis nws yuav tsum tau muab sau tseg tias 75-ohm grounding resistance nyob rau hauv kab yuav tsum tau muab tso rau ze. mus rau lub davhlau ya nyob twg tus pin. Feem ntau siv PP.