Nrog rau qhov muaj hnub nyoog ntawm cov ntaub ntawv, kev siv pcb boards tau dhau los ua ntau thiab ntau dua, thiab kev txhim kho ntawm pcb boards tau dhau los ua ntau thiab nyuaj.Raws li cov khoom siv hluav taws xob tau teeb tsa ntau dua thiab ntom ntom ntawm PCB, kev cuam tshuam hluav taws xob tau dhau los ua qhov teeb meem uas yuav tsum tau zam.Hauv kev tsim thiab kev siv ntawm ntau txheej boards, lub teeb liab txheej thiab lub hwj chim txheej yuav tsum tau sib cais, yog li kev tsim thiab kev npaj ntawm pawg yog qhov tseem ceeb tshwj xeeb.Lub tswv yim tsim qauv zoo tuaj yeem txo qhov cuam tshuam ntawm EMI thiab crosstalk hauv ntau pawg.
Muab piv nrog cov txheej txheem ib txheej zoo tib yam, kev tsim cov txheej txheem ntau txheej ntxiv cov teeb liab txheej, txheej txheej, thiab npaj cov txheej txheem hluav taws xob ywj pheej thiab cov txheej hauv av.Qhov zoo ntawm ntau txheej boards yog qhov tseem ceeb hauv kev muab qhov hluav taws xob ruaj khov rau kev hloov pauv cov teeb liab digital, thiab sib npaug ntxiv lub zog rau txhua qhov khoom nyob rau tib lub sijhawm, txo qhov cuam tshuam ntawm cov teeb liab.
Lub zog hluav taws xob yog siv nyob rau hauv thaj tsam loj ntawm tooj liab tso thiab hauv av txheej, uas tuaj yeem txo qhov tsis kam ntawm lub hwj chim txheej thiab txheej hauv av, kom qhov hluav taws xob ntawm lub hwj chim txheej ruaj khov, thiab cov yam ntxwv ntawm txhua kab teeb liab. tuaj yeem lav, uas yog qhov zoo heev rau impedance thiab crosstalk txo.Nyob rau hauv kev tsim ntawm high-end circuit boards, nws tau hais meej meej tias yuav tsum siv ntau tshaj 60% ntawm cov txheej txheem stacking.Multi-txheej boards, cov yam ntxwv hluav taws xob, thiab kev tiv thaiv hluav taws xob hluav taws xob txhua qhov muaj qhov zoo sib xws ntawm cov txheej txheem qis.Nyob rau hauv cov nqe lus ntawm tus nqi, feem ntau hais lus, ntau cov khaubncaws sab nraud povtseg muaj, tus nqi kim dua, vim hais tias tus nqi ntawm lub rooj tsavxwm PCB muaj feem xyuam rau tus naj npawb ntawm cov txheej, thiab qhov ceev ntawm ib chav tsev.Tom qab txo tus naj npawb ntawm cov khaubncaws sab nraud povtseg, qhov chaw xaim yuav raug txo kom tsawg, yog li ua kom cov xaim ceev., thiab txawm tias ua tau raws li cov qauv tsim los ntawm kev txo cov kab dav thiab kev ncua deb.Cov no tuaj yeem nce nqi kom tsim nyog.Nws muaj peev xwm txo tau cov stacking thiab txo tus nqi, tab sis nws ua rau cov hluav taws xob ua haujlwm tsis zoo.Hom kev tsim no feem ntau yog counterproductive.
Saib ntawm PCB microstrip thaiv ntawm tus qauv, txheej hauv av kuj tuaj yeem suav tias yog ib feem ntawm cov kab sib kis.Cov txheej tooj liab hauv av tuaj yeem siv los ua lub teeb liab kab voj kab.Lub dav hlau fais fab txuas nrog lub dav hlau hauv av los ntawm lub tshuab hluav taws xob decoupling, nyob rau hauv rooj plaub ntawm AC.Ob leeg sib npaug.Qhov txawv ntawm qhov tsawg zaus thiab siab zaus tam sim no loops yog qhov ntawd.Ntawm qhov tsawg zaus, qhov rov qab tam sim no ua raws li txoj hauv kev ntawm qhov tsawg kawg nkaus tsis kam.Nyob rau hauv high zaus, qhov rov qab tam sim no yog raws txoj kev ntawm qhov tsawg kawg nkaus inductance.Qhov tam sim no rov qab, concentrated thiab faib ncaj qha hauv qab cov teeb liab kab.
Nyob rau hauv cov ntaub ntawv ntawm high zaus, yog hais tias ib tug hlau yog ncaj qha mus pw rau hauv av txheej, txawm yog hais tias muaj ntau loops, tam sim no rov qab yuav ntws rov qab mus rau lub teeb liab qhov chaw los ntawm lub thaiv txheej nyob rau hauv lub keeb kwm txoj kev.Vim txoj kev no muaj qhov tsawg kawg nkaus impedance.Hom kev siv loj capacitive txuas los txhawm rau txhawm rau txhawm rau hluav taws xob, thiab qhov tsawg kawg nkaus capacitive coupling txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau txhawm rau tiv thaiv qis, peb hu nws tus kheej tiv thaiv.
Nws tuaj yeem pom los ntawm cov qauv uas thaum lub sijhawm tam sim no ntws rov qab, qhov kev ncua deb ntawm kab teeb liab yog inversely proportional rau qhov ceev tam sim no.Qhov no minimizes lub voj cheeb tsam thiab inductance.Nyob rau tib lub sijhawm, nws tuaj yeem txiav txim siab tias yog qhov kev ncua deb ntawm kab teeb liab thiab lub voj voog ze, cov dej ntws ntawm ob qhov zoo sib xws hauv qhov loj thiab qhov sib txawv ntawm kev coj.Thiab cov hlau nplaum tsim los ntawm qhov chaw sab nraud tuaj yeem raug offset, yog li EMI sab nraud kuj tseem me me.Nyob rau hauv pawg tsim, nws yog qhov zoo tshaj plaws kom muaj txhua lub teeb liab kab sib haum mus rau ib txheej hauv av ze heev.
Nyob rau hauv qhov teeb meem ntawm crosstalk rau hauv av txheej, crosstalk tshwm sim los ntawm high-frequency circuits yog vim inductive coupling.Los ntawm cov qauv voj voog saum toj no, nws tuaj yeem txiav txim siab tias lub voj voog tam sim no tsim los ntawm ob lub teeb liab kab ze ua ke yuav sib tshooj.Yog li yuav muaj kev cuam tshuam sib nqus.
K nyob rau hauv cov mis muaj feem xyuam rau lub teeb liab nce lub sij hawm thiab qhov ntev ntawm cov kab teeb liab cuam tshuam.Hauv kev teeb tsa pawg, shortening qhov kev ncua deb ntawm lub teeb liab txheej thiab txheej hauv av yuav zoo txo qhov cuam tshuam los ntawm cov txheej hauv av.Thaum muab tooj liab tso rau ntawm cov khoom siv hluav taws xob thiab cov txheej hauv av ntawm PCB thaiv, cov phab ntsa sib cais yuav tshwm sim hauv thaj chaw tooj liab yog tias koj tsis xyuam xim.Qhov tshwm sim ntawm cov teeb meem no feem ntau yuav yog vim lub siab siab ntawm lub qhov, lossis cov qauv tsis tsim nyog ntawm thaj chaw cais.Qhov no slows down lub sij hawm nce thiab nce lub voj cheeb tsam.Inductance nce thiab tsim crosstalk thiab EMI.
Peb yuav tsum sim peb qhov zoo tshaj plaws los teeb tsa lub khw lub taub hau ua khub.Qhov no yog nyob rau hauv kev txiav txim siab ntawm cov qauv kev tshuav nyiaj li cas hauv cov txheej txheem, vim tias cov qauv tsis sib npaug tuaj yeem ua rau deformation ntawm pcb board.Rau txhua lub teeb liab txheej, nws yog qhov zoo tshaj plaws kom muaj lub nroog zoo tib yam li lub caij nyoog.Qhov kev ncua deb ntawm high-end fais fab mov thiab lub nroog tooj liab yog qhov tsim nyog rau kev ruaj ntseg thiab txo EMI.Nyob rau hauv high-speed board tsim, redundant av dav hlau yuav muab ntxiv rau cais cov teeb liab dav hlau.
Post lub sij hawm: Mar-23-2023