Nge hole (VIA) kuyingxenye ebalulekile ye- multilayer PCB, futhi izindleko zemigodi yokumba zivame ukubalwa ngama-30% kuya ku-40% wezindleko zokwenza ibhodi le-PCB. Kalula nje, yonke imbobo ku-PCB ingabizwa ngokuthi umgodi wokudlula. Ngokuya ngomsebenzi, umgodi ungahlukaniswa ngezigaba ezimbili: esisodwa sisetshenziselwa ukuxhumana kagesi phakathi kwezendlalelo; Enye isetshenziselwa ukulungisa idivayisi noma ukuma.

Ngokwenqubo, lezi zimbobo ezihlukaniswayo ngokuvamile zihlukaniswe izigaba ezintathu, okungukuthi, i-blind via, ingcwatshwe nge-through nange-through. Izimbobo eziyimpumputhe zitholakala ezindaweni eziphezulu nezingezansi zebhodi lesifunda elinyathelisiwe futhi zinokujula okuthile kokuxhuma isifunda esingaphezulu kwesifunda esingaphakathi ngezansi. Ukujula kwemigodi imvamisa akweqi isilinganiso esithile (ukuvula). Izimbobo ezingcwatshwe izimbobo zokuxhuma kusendlalelo sangaphakathi sebhodi lesifunda eliphrintiwe elingadluli ebusweni bebhodi lesifunda eliphrintiwe. Izinhlobo ezimbili zezimbobo zitholakala engxenyeni yangaphakathi yebhodi lesifunda, eligcwaliswa ngenqubo yokubumba emgodini ngaphambi kokuhlungwa, futhi izingqimba eziningana zangaphakathi zingagqitshwa ngesikhathi kwakhiwa imbobo. Uhlobo lwesithathu, olubizwa nge-through-hole, ligijima kulo lonke ibhodi lesifunda futhi lungasetshenziselwa ukuxhumana kwangaphakathi noma njengokufaka nokuthola izimbobo zezinto ezithile. Ngoba umgodi wokungena kulula ukuwusebenzisa kule nqubo, izindleko ziphansi, ngakho-ke amabhodi wesifunda amaningi aprintiwe ayayisebenzisa, kunezinye izinhlobo ezimbili zomgodi. Lokhu okulandelayo ngemigodi, ngaphandle kwencazelo ekhethekile, kuzobhekwa njengokungena emigodini.

Wazi kangakanani nge-PCB design hole

Ngokombono wokuklama, umgodi odabula ikakhulukazi unezingxenye ezimbili, enye imbobo yokubhoboza maphakathi kanti enye indawo yephedi ezungeze umgodi wokubhola, njengoba kukhonjisiwe kumfanekiso ongezansi. Usayizi walezi zingxenye ezimbili unquma usayizi wembobo edlulayo. Ngokusobala, ekwakhiweni kwe-high-speed, high-density PCB, umklami uhlala efuna ukuthi umgodi ube mncane ngangokunokwenzeka, lesi sampuli singashiya isikhala sokwengeza izintambo, ngaphezu kwalokho, okuncane emgodini, amandla aso okuphila kwezinambuzane mancane, ngaphezulu ifanele isifunda esinejubane elikhulu. Kepha usayizi womgodi uyancipha ngasikhathi sinye uletha ukwanda kwezindleko, futhi ubukhulu bomgodi abungehliswa ngaphandle komkhawulo, kukhawulwe ngokubhola (ukubhola) nokufaka (ukugoqa) nobunye ubuchwepheshe: imbobo encane, kuthatha isikhathi eside ukubhola, kuba lula ukusuka enkabeni; Lapho ukujula komgodi kuphindwe izikhathi ezingaphezu kwezingu-6 ububanzi bomgodi, akunakwenzeka ukuqinisekisa ukufakwa kopende ofanayo wodonga lomgodi. Isibonelo, ukushuba okujwayelekile kwamanje (ngokusebenzisa ukujula komgodi) kwebhodi le-PCB elino-6 kumayelana ne-50Mil, ngakho-ke ubukhulu obuncane bokubhola abakhiqizi be-PCB abangabunikeza bungafika ku-8Mil kuphela. Amandla we-parasitic womgodi ngokwawo akhona phansi, uma ububanzi bembobo yokuhlukaniswa kungu-D2, ububanzi bephedi yomgodi yi-D1, ubukhulu bebhodi le-PCB ngu-T, kanye nokuqina kwe-dielectric kwe-substrate yi-ε, amandla we-parasitic womgodi cishe: C = 1.41εTD1 / (D2-D1)

Umphumela oyinhloko we-capacitance yama-parasitic ukwengeza isikhathi sokunyuka kwesiginali nokunciphisa ijubane lesifunda. Isibonelo, ebhodini le-PCB elinobukhulu be-50Mil, uma ububanzi bangaphakathi bomgodi bungu-10Mil, ububanzi bephedi bungu-20Mil, futhi ibanga eliphakathi kwephedi nendawo yethusi lingu-32Mil, singalinganisela amandla we-parasitic yomgodi ngokusebenzisa ifomula engenhla: C = 1.41 × 4.4 × 0.050 × 0.020 / (0.032-0.020) = 0.517pF, ukwehluka kwesikhathi sokuphakama okubangelwa yile ngxenye ye-capacitance yile: T10-90 = 2.2C (Z0 / 2) = 2.2 × 0.517x (55 / 2) = 31.28ps. Kusukela kulawa magugu, kusobala ukuthi yize umthelela we-capacitance ye-parasitic kusuka emgodini owodwa ekubambezelekeni kokuphakama ungabonakali, abaklami kufanele baqaphele uma kusetshenziselwa izimbobo eziningi ekushintsheni koqweqwe lukalayini.

Ekudizayineni kwamasekethe edijithali ashesha kakhulu, ukufakwa kwesidlakudla se-inductance yesinambuzane emgodini kuvame ukuba kukhulu kunomthelela we-capacitance ye-parasitic. Ukungeniswa kwayo kochungechunge lwe-parasitic kuzothena amandla umnikelo we-bypass capacitance futhi kunciphise ukusebenza kokuhlunga kohlelo lonke lwamandla. Singamane sibale ukungeniswa kwesinambuzane sokulinganiselwa kwembobo ngokusebenzisa ifomula elandelayo: L = 5.08h [ln (4h / d) +1] lapho u-L ebhekisa ekungeneni kwembobo, h ubude bokudlula- umgodi, no-D ububanzi bomgodi ophakathi. Kungabonakala kusukela ku-equation ukuthi ububanzi bomgodi bunomthelela omncane ekungenisweni, ngenkathi ubude bomgodi bunomthelela omkhulu ekungenisweni. Usasebenzisa lesi sibonelo esingenhla, ukwehliswa komgodi kungabalwa njengo-L = 5.08 × 0.050 [ln (4 × 0.050 / 0.010) +1] = 1.015nh. Uma isikhathi sokuvuka kwesiginali singu-1ns, khona-ke usayizi we-impedance olinganayo uthi: XL = πL / T10-90 = 3.19 ω. Le impedance ayinakunakwa lapho kukhona imvamisa ephezulu yamanje. Ikakhulu, i-bypass capacitor kufanele idlule emigodini emibili yokuxhuma ungqimba lokuphakelwa ekwakhekeni, ngaleyo ndlela iphindwe kabili ukufakelwa kwesinambuzane somgodi.

Ngokuhlaziywa okungenhla kwezimpawu zezimbobo zomgodi, siyabona ukuthi ekwakhiweni kwejubane le-PCB, umgodi obonakala ulula uvame ukuletha imiphumela emibi emiklamo yesifunda. Ukuze sinciphise imiphumela engemihle yomthelela wesinambuzane somgodi, singenza okuningi ngangokunokwenzeka ekwakhiweni: 1. Kusuka ezicini ezimbili zezindleko nezinga lesiginali, khetha ubukhulu obufanele bomgodi. Isibonelo, ngezingqimba eziyi-6-10 zedizayini ye-MEMORY module PCB, kungcono ukhethe i-10 / 20mil (imishini / iphedi) ngembobo, ngamanye amabhodi amancane osayizi abakhulu, ungazama futhi ukusebenzisa i-8 / 18mil ngokusebenzisa umgodi. Ngobuchwepheshe bamanje, kungaba nzima ukusebenzisa izimbobo ezincane. Ukuhlinzekwa kwamandla noma ucingo lwaphansi ngokusebenzisa izimbobo kungabhekwa njengokusebenzisa usayizi omkhulu ukunciphisa impedance.

2. Amafomula amabili okuxoxwe ngawo ngenhla akhombisa ukuthi ukusetshenziswa kwamabhodi e-PCB amancane kusiza ukunciphisa imingcele emibili yezinambuzane ngokusebenzisa izimbobo.

3. izintambo zesiginali ebhodini le-PCB akufanele zishintshe ungqimba ngangokunokwenzeka, okungukuthi, zama ukungasebenzisi izimbobo ezingadingekile.

4. Izikhonkwane zokuphakelwa kukagesi kanye nomhlabathi kufanele kubhodwe eduzane. Okufushane ukuhola phakathi kwezikhonkwane nezimbobo, kuba ngcono, ngoba kuzoholela ekwandeni kokungeniswa. Ngasikhathi sinye, ukuhola kwamandla nomhlabathi kufanele kube mkhulu ngangokunokwenzeka ukunciphisa impedance.

5. Beka ezinye izimbobo zokubeka phansi eduze kwezimbobo zoshintsho lwesendlalelo sesiginali ukuze unikeze iluphu eseduzane yesiginali. Ungafaka nezimbobo eziningi ezingeziwe ku-PCB. Vele, udinga ukuguquguquka ekwakhiweni kwakho. Imodeli yembobo okuxoxwa ngayo ngenhla yisimo lapho kunamapads kusendlalelo ngasinye. Kwesinye isikhathi, singanciphisa noma sisuse amapayipi kwezinye izingqimba. Ikakhulukazi esimweni sokuminyana komgodi sikhulu kakhulu, kungaholela ekwakhiweni komsele wesifunda osikiwe kungqimba lwethusi, ukuxazulula inkinga enjalo ngaphezu kokuhambisa indawo yomgodi, singacabanga nangembobo kusendlalelo sethusi ukunciphisa usayizi wephedi.