Usarega PCB vias ichiparadza bhodhi rako rose

Usarega PCB vias ichiparadza bhodhi rako rese! Vias chikamu chakakosha chePCBs dzine layer yakawanda , nemari yekuboorera inowanzoita 30% kusvika 40% yemari yekugadzira PCB. Muchidimbu, buri rega rega riri paPCB rinogona kunzi via.

PCB drilling classification

Kubva pakuona kwekushanda, vias inogona kukamurwa kuita mapoka maviri:

Kubatana Kwemagetsi Pakati Pematanho: Inoshandiswa kubatanidza zvidimbu zvakasiyana zvePCB nekuda kwemagetsi.
Fixture kana Positioning yeZvikamu: Inoshandiswa kugadzirisa kana kuisa zvikamu.

Kubva pakuona kwemaitiro, aya vias anowanzo kukamurwa kuva marudzi matatu:

Mabofu, akavigwa vias, uye kuburikidza vias.

Blind Vias: Iri pamusoro uye pasi pezviso zvePCB, vias izvi zvine humwe hudzamu uye dzinoshandiswa kubatanidza maronda emukati kune maronda emukati. Kudzika kwegomba kazhinji hakupfuuri imwe chiyero (diameter).
Kuvigwa Vias: Aya mavias ari mukati memukati mezvikamu zvePCB, kwete kuenderera kumusoro kwebhodhi. Zvose izvi mhando vias zviri mukati mukati akaturikidzana PCB uye anoumbwa pamberi lamination vachishandisa kuburikidza-gomba kuumba muitiro, izvo zvinogona anopindirana anoverengeka yomukati akaturikidzana panguva Via kuumbwa.
Kuburikidza neVias: Iyi vias inopfuura nepakati pePCB yese uye inogona kushandiswa mukati mekubatana kana semaburi ekukwira ezvikamu.

Nemhaka yavo nyore kushandisa mukugadzira muitiro uye yakaderera mutengo, vakawanda zvikuru yakadhindwa redunhu mapuranga anoshandisa kuburikidza vias pane mamwe marudzi maviri vias. Kunze kwekunge kwatsanangurwa neimwe nzira, iyo vias inotaurwa pazasi inotariswa kuburikidza neas.

Kubva pamaonero ekugadzira, via via kunyanya rine zvikamu zviviri:

• Kufunga Nezvezvikamu uye Kugadzira : Dhizaini yePCB ine gomba repakati rakakomberedzwa nenzvimbo yepedhi, uko saizi yezvikamu izvi inosarudza saizi yePCB yese. Mumadhizaini ePCB ane kumhanya kwakanyanya uye akasimba, kuderedza saizi kwakakosha kuti nzvimbo yekufambisa iendeswe zvakanaka uye kuderedza kugona kweparasite, zvichiwedzera kukodzera kwecircuits dzinomhanya zvakanyanya.

• Zvipingamupinyi zveMutengo neSaizi : Zvisinei, kudzikira kuburikidza nehukuru kunowedzera mitengo yekugadzira nekuda kwenguva refu yekuboorera uye kukanganisa kunogona kuitika panguva yekuita senge kuboorera nekuputira. Kana kudzika kwegomba kuchipfuura katanhatu dhayamita yaro, kuve nechokwadi chekuti jira remhangura rakafanana pamadziro egomba kunova kwakaoma, zvichikanganisa mutengo uye kugona kugadzirwa.

• Kufambira Mberi Kwetekinoroji uye Microvias : Kufambira mberi kwazvino muhunyanzvi hwekuboorera nelaser kwakaita kuti zvikwanisike kushandisa ma-vias madiki. Ma-vias ane dhayamita ye6 mils kana pasi anonzi ma-microvias uye anowanzo shandiswa muHDI designs. Ma-microvias aya anotsigira magadzirirwo e-via-in-pad, zvichivandudza mashandiro ecircuit uye kuchengetedza nzvimbo yekufambisa paPCB.

• Kunetseka Nezvekusimba Kwechiratidzo : MaVias anounza kusagadzikana kweimpedance mumitsetse yekutumira, izvo zvinogona kutungamira kukuratidzira kwechiratidzo. Impedance yea via yakaderera ne12% pane iyo yemutsetse wekutumira, zvichikonzera kudzikira kudiki kweimpedance. Pasinei neizvi, chiyero chaicho chekuratidzira hachina kuenzana, kazhinji kacho chiri pa0.06, nekuda kwemaitiro ekugadzira akachengetedzwa zvakanaka uye matekiniki ekugadzira.

• Kukwanisa Kupinza Masimba uye Kupinza Masimba : Matambudziko makuru ane chekuita nemavias mukugadzirwa kwePCB ane chekuita nekutarisira migumisiro yezvipembenene zvakaita se capacitance uye inductance. Zvinhu izvi zvakakosha mukugadzirwa kwema frequency akakwirira uko kuchengetedza kunaka kwemasaini uye kuderedza kurasikirwa kwekutumira kwakakosha.

 Parasitic Capacitance uye Inductance yeVias

Parasitic Capacitance yeVias

Vias pachavo vane parasitic capacitance pasi. Kana iyo yekuzviparadzanisa yegomba dhayamita yeya papasi pevhu ichizivikanwa kuve D2, uye padhi dhayamita yeVia iri D1, ine PCB ukobvu hweT uye substrate dielectric garage ye ε, iyo parasitic capacitance yeVia ingangoita. :

C=1.41εTD1/(D2−D1)

Iyo parasitic capacitance yeiyo via ichanyanya kukanganisa kusimuka kwechiratidzo, ichideredza kumhanya kwedunhu. Semuenzaniso, yePCB ine hukobvu hwemamirimita makumi mashanu, kana via ine dhayamita yemukati me50 mils uye padhi dhayamita ye10 mils inoshandiswa, uye chinhambwe chiri pakati pepadhi nenzvimbo yemhangura yepasi i20 mils, iyo parasitic. capacitance ye Via inogona kuverengerwa se:

C=1.41×4.4×0.050×0.020/(0.032−0.020)=0.517pF

Shanduko yenguva yekusimuka inokonzerwa neichi capacitance ndeiyi:

T10−90​=2.2C(Z0​/2)=2.2×0.517×(55/2)=31.28ps

Kunyange zvazvo mhedzisiro ye capacitance yeimwe chete kuburikidza nekusimuka nguva haisi pachena, kana vias inoshandiswa kakawanda mukufambisa kwe interlayer switching, vagadziri vanofanira kuramba vachifunga nezvazvo.

Parasitic Inductance yeVias

Parasitic Inductance yeVias Saizvozvo, nepo vias ine parasitic capacitance, ivo zvakare vane parasitic inductance. Mukugadzirwa kwemasekete ekumhanya kwedhijitari, kukuvadzwa kunokonzerwa neparasitic inductance ye vias kunowanzo hukuru kupfuura iyo yeparasitic capacitance. Iyo parasitic series inductance inoderedza mupiro we bypass capacitance uye inoderedza kusefa kweiyo yese magetsi system.

Isu tinogona kushandisa inotevera fomula kuverenga iyo inofungidzirwa parasitic inductance yea via:

L=5.08h[ln(4h/d)+1]

Iko L ndiko kudhonzwa kweiyo via, h ndiko kureba kweiyo via, uye d ndiyo dhayamita yepakati peburi rekuchera. Kubva pane fomula, zvinogona kuoneka kuti dhayamita yeVia ine diki mhedzisiro pane inductance, nepo kureba kweiyo via kunokanganisa inductance. Tichishandisa muenzaniso uri pamusoro, tinogona kuverenga inductance yeiyo via sezvinotevera:

L=5.08×0.050[ln(4×0.050/0.010)+1]=1.015nH

Kana nguva yekusimuka kwechiratidzo iri 1 ns, saka yakaenzana impedance ndeiyi:

XL=πL/T10−90​=3.19Ω

Iyo impedance yakadaro haigone kufuratirwa kana paine yakakwira-frequency ikozvino inopfuura. Kunyanya, kana uchibatanidza bypass capacitor kune simba uye pasi akaturikidzana, inoda kupfuura neaviri vias, izvo zvakapetwa kaviri parasitic inductance ye via.

Via Dhizaini mune Yakakwira-Speed ​​PCBs

Kuburikidza nekuongororwa kweparasitic maitiro e vias pamusoro, zvinogona kuoneka kuti mukumhanya-mhanya PCB dhizaini, inoratidzika kunge iri nyore vias kazhinji inogona kuunza yakakosha mhedzisiro kudhizaini dhizaini.

Kuti uderedze mhedzisiro yeparasitic mhedzisiro yevias, zvinotevera zvirimo zvinogona kurongeka mudhizaini zvakanyanya sezvinobvira:

Sarudza vias ehukuru hunonzwisisika uchifunga zvese mutengo uye chiratidzo chemhando. Semuenzaniso, yePCB dhizaini ye6-10 layer memory modules, zviri nani kushandisa vias ine dhayamita ye10/20 mils (gomba rekuchera/pedhi). Kune mamwe mabhodhi madiki akakwira-density, unogona zvakare kuedza kushandisa 8/18 mils vias. Pasi pezvino tekinoroji mamiriro, zvakaoma kushandisa diki vias. Kune simba kana pasi vias, funga kushandisa hukuru hukuru kuderedza impedance.

Sezvakakurukurwa pamusoro, kushandisa mutete PCB kunobatsira kuderedza maviri parasitic parameters pamusoro vias.
Simba uye pasi pini zvinofanira kuiswa pedyo sezvinobvira kuti vias, uye zvinotungamirira pakati vias uye mapini anofanira kuva pfupi sezvinobvira, sezvo vachawedzera inductance. Panguva imwecheteyo, zvinotungamira zvesimba uye pasi zvinofanirwa kunge zvakakora sezvinobvira kuderedza impedance.

Edza kuderedza kushandiswa vias nokuda chiratidzo routing pamusoro PCB, kureva, edza kuderedza kusingakoshi vias.
Isa imwe grounding vias pedyo vias apo chiratidzo kuchinja akaturikidzana kupa pedyo kudzoka nzira nokuda chiratidzo. Iwe unogona kutoisa nhamba yakakura yeadhindant grounding vias paPCB. Zvechokwadi, kushanduka uye kuchinja kunodiwawo mukugadzira.

Nhaurirano iri pamusoro peiyo modhi inofungidzira kuti imwe neimwe layer ine mapadhi. Dzimwe nguva, isu tinokwanisa kuderedza kana kutobvisa mapadhi pane mamwe maseru. Kunyanya kana density ye vias yakakwira kwazvo, inogona kuita kuti slot iite chinovharira loop mumhangura layer. Pamusoro pekufambisa chinzvimbo cheiyo via, isu tinogona zvakare kufunga kudzikisa saizi yepadhi repadhi padanda remhangura.

mhedziso

PCB vias zvinhu zvakakosha mu-multi-layer PCBs, inoverengera chikamu chakakosha chemitengo yekugadzira. Vias dzakakamurwa zvichienderana nebasa radzo sekupa magetsi ekubatanidza pakati pematanho kana kushanda sezvigadziriso zvezvikamu. Kubva pakuona kwemaitiro, vias zvinokamurwa kuita bofu, kuvigwa, uye kuburikidza vias. Nepo bofu uye akavigwa vias dziri mukati mukati akaturikidzana PCB, kuburikidza vias kupfuura bhodhi rose.

Vagadziri vanovavarira kushandisa ma-vias madiki muma- PCB ane kumhanya kwakanyanya uye ane huwandu hwakawanda hwezvinhu kuti vawedzere nzvimbo yekufambisa zvinhu uye vaderedze kugona kwezvipembenene. Zvisinei, pane miganhu yekuderedza saizi nekuda kwezvirambidzo zvekugadzira zvakaita sekuboora nekuisa maplate. Kuvandudzwa kwetekinoroji yekuchera nelaser kwakaita kuti kushandiswa kwema-microvias kuwedzere, zvichivandudza mashandiro edunhu uye kuchengetedza nzvimbo.

Pasinei nemabhenefiti avo, vias inogona kuunza impedance discontinuities pamitsara yekutapurirana, zvichikonzera kushoma chiratidzo chekuratidzira. Nyaya huru dzine vias dzine chokuita neparasitic capacitance uye inductance, iyo inogona kukanganisa kukurumidza kwechiratidzo uye kusefa mumakwikwi edhijitari. Kudzikamisa izvi zvinokonzeresa, vagadziri vanofanirwa kunyatso funga kuburikidza nehukuru, kuiswa, uye nzira dzenzira mune yakakwirira-kumhanya PCB dhizaini.