I-Via ingenye yezinto ezibalulekile ze-PCB ehlukahlukene, kanti izindleko zokumba zivame ukubalwa kwama-30% kuya ku-40% wezindleko zebhodi le-PCB. Kalula nje, wonke umgodi kwi-PCB ungabizwa nge-via.
Umqondo oyisisekelo we-Via:
Ukusuka endaweni yokubuka umsebenzi, i-Via ingahlukaniswa izigaba ezimbili: I-One isetshenziswa njengokuxhumeka kukagesi phakathi kwezendlalelo, kanti enye isetshenziswa njengokuhlelwa kwensiza noma ukuma kwensiza. Uma kusuka kwinqubo, lezi zimbobo zihlukaniswa ngezigaba ezintathu, okungukuthi izimbobo ezingaboni, izimbobo ezingcwatshwe kanye nezimbobo.
Izimbobo eziyimpumputhe zitholakala ezingxenyeni eziphezulu nezingaphansi zebhodi yokujikeleza ephrintiwe futhi zinokujula okuthile kokuxhumeka kwesifunda esingaphezulu nendawo esiseduze, futhi ukujula kwezimbobo ngokuvamile akungeqi isilinganiso esithile (i-aperture).
Umgodi ongcwatshwe ubhekisele emgodini wokuhlanza otholakala engxenyeni engaphakathi yebhodi yesekethe ephrintiwe, engadluliseli ebusweni beBhodi. Lezi zinhlobo ezimbili ezingenhla kwezimbobo zitholakala engxenyeni yangaphakathi yebhodi yesekethe, eliphothulwa yinqubo yokubumba yomgodi ngaphambi kokugcwala, futhi izingqimba eziningana zangaphakathi zingahle ziboshwe ngesikhathi sokwakhiwa komgodi.
Uhlobo lwesithathu lubizwa nge-patos, oludlula kulo lonke ibhodi yesekethe futhi lungasetshenziswa ukufeza ukuxhumana kwangaphakathi noma njengezimbobo zokufaka ezingxenyeni. Ngoba i-hole kulula ukuyifinyelela kwinqubo futhi izindleko ziphansi, iningi lamabhodi wesifunda aphrintiwe alisebenzisa, kunokuba amanye amabili anezimbobo ezimbili. Izimbobo ezilandelayo, ngaphandle kwemiyalo ekhethekile, kubhekwa njengezimbobo.
Ukusuka endaweni yokubuka, i-via ikakhulukazi yakhiwa izingxenye ezimbili, enye iphakathi komgodi wokumba, kanti enye indawo ye-welding pad ezungeze umgodi wokumba. Usayizi walezi zingxenye ezimbili unquma usayizi we-via.
Ngokusobala, ngesivinini esikhulu, abaklami be-PCB ephezulu kakhulu, abaqambi bahlala bafuna umgodi omncane ngangokunokwenzeka, ngakho-ke isikhala se-wiring esiningi singashiywa, ngaphezu kwalokho, ukuncipha kwe-capicititic kuncane, kufanelekile kakhulu imibuthano ephezulu.
Kodwa-ke, ukuncishiswa kosayizi we-via futhi kuletha ukwanda kwezindleko, kanti usayizi womgodi awukwazi ukwehliswa unomphela, kukhawulelwe ubuchwepheshe bokumba kanye ne-elekhreni, isikhathi eside ukuthambekela enkabeni; Lapho ukujula komgodi kungaphezu kwezikhathi ezi-6 ububanzi bomgodi, akunakwenzeka ukuqinisekisa ukuthi udonga lweHole lungalinganiswa ngokufana nethusi.
Isibonelo, uma ubukhulu be-hole (ngokujula kwembobo) yebhodi elijwayelekile le-PCB le-6mil lingama-50mil, khona-ke ububanzi bokumba abakhiqizi be-PCB bunganikeza ngaphansi kwezimo ezijwayelekile. Ngokuthuthukiswa kobuchwepheshe bokumba ama-laser, ubukhulu bokumba bungaba buncane futhi buncanyana, futhi ububanzi bomgodi buvame ukungaphansi noma ukulingana nama-6mils, abizwa ngama-microholes.
Ama-Microholes ajwayele ukusetshenziswa ku-HDI (I-High density InterConnect SAMECK), kanye nobuchwepheshe be-microhole kungavumela umgodi obizwe ngqo ephepheni, okuthuthukisa kakhulu ukusebenza kwesekethe futhi kusindise isikhala se-wiring. I-Via ivela njengembuka ye-litedance discontinuty emugqeni wokuhambisa, okubangela ukuboniswa kwesiginali. Ngokuvamile, ukungcola okulinganayo komgodi kucishe kube ngu-12% ngaphansi komugqa wokuhambisa, ngokwesibonelo, ukungcola komugqa wokuhanjiswa kwe-50 ohms kuzoncishiswa ngama-6 ohms lapho kudlula ku-via, ubukhulu bepuleti kuhlobene nalo, hhayi ukuncishiswa ngokuphelele).
Kodwa-ke, ukuboniswa okubangelwa ukunqanyulwa kwe-Imponciantity nge-Empeleni kuyingcane kakhulu, futhi i-coeffection yayo yokubonisa kuphela:
(44-50) / (44 + 50) = 0.06
Izinkinga ezivela ku-Via zigxile kakhulu emiphumeleni yokukhohlisa kanye nokufakwa.
I-Capitance Capecitance ye-Via
Kukhona amandla okuphambuka okuphambanisa nge-wiya uqobo. Uma ububanzi bendawo yokumelana ne-soled ku-wayer elibekwe yi-D2, ububanzi be-soler pad ngu-D1, ubukhulu be-PCB Bhodi i-D1, futhi i-dielectric ihlala njalo, amandla okubuyisana ahamba nge-pay,
C = 1.41Imputer1 / (D2-D1)
Umphumela ophambili wokuphambanisa kwamanani okuhambisana nalokhu ukwandisa isikhathi sokukhuphuka kwesiginali futhi unciphise ijubane lesifunda.
Isibonelo, nge-PCB enobukhulu bama-50mil, uma ubukhulu be-via pad ingu-20mil (ububanzi bomgodi wokumba yi-10mils) kanye nobubanzi bendawo yokumelana ye-soleril, khona-ke singalinganiselwa amandla okuhambisana nalesi sigameko sefomula engenhla:
C = 1.41x4.4x0.050x0.020 / (0.040-0.020) = 0.31PF
Inani lokushintshwa kwesikhathi sokukhuphuka okubangelwa yile ngxenye ye-capacitance cishe:
I-T10-90 = 2.2C (Z0 / 2) = 2.2x0.31x (50/2) = 17.05ps
Kungabonakala kusuka kulezi zinqumo yize ukusetshenziswa kokubambezeleka kokuphakanyiswa okubangelwa ukukhokhwa kwamandla okuqala okukodwa akubonakali kakhulu, uma ngabe i-via isetshenziswa kaningi, futhi i-design kufanele ibhekwe ngokucophelela. Ekwakhiweni kwangempela, ukusebenzisa amandla okuhambisana nakho kungancishiswa ngokwandisa ibanga phakathi kwembobo nendawo yethusi (anti-pad) noma ukunciphisa ububanzi be-pad.
Ekwakhiweni kwemibuthano yedijithali ephezulu kakhulu, ukulimala okubangelwa ukuwohloka kwe-parasitic kuvame kakhulu kunethonya lokuphaphama. I-Parasitic Series yayo ye-Parasitic izokwenza buthaka umnikelo we-pasacitor ye-bypass futhi yenze buthaka ukusebenza kohlunga kohlelo lwamandla wonke.
Singasebenzisa ifomula elandelayo enamandla ukumane balale ukufakwa kwe-parasitic kwe-pay-hole accerimation:
L = 5.08h [ln (4h / d) +1]
Lapho l kubhekiswa ekunciphiseni kwe-via, h ubude be-via, futhi d ububanzi bomgodi ophakathi nendawo. Kungabonakala kusuka kwifomula yokuthi ububanzi be-via buthonya elincane ekuqothulweni, kuyilapho ubude be-via bunethonya elikhulu kunawo wonke elongwini. Usasebenzisa isibonelo esingenhla, ukufakwa kwe-out-of-hole kungabalwa njenge:
L = 5.08x0.050 [ln (4x0.050 / 0.010) +1] = 1.015NH
Uma isikhathi sokukhuphuka kwesiginali singama-1ns, khona-ke usayizi wawo ofanayo wokulimaza ngukuthi:
XL = πL / T10-90 = 3.199ω
Ukuphazamiseka okunjalo akunakunakwa phambi kwemvamisa ephezulu, ikakhulukazi, qaphela ukuthi i-pasacitor ye-bypass idinga ukudlula izimbobo ezimbili lapho umgodi wamandla, ukuze umgodi we-parasitic womgodi uzophindaphindeka.
Ungayisebenzisa kanjani i-Via?
Ngokuhlaziywa okungenhla kwezimpawu zokuhlanzeka komgodi, singakubona lokho kumklamo we-PCB we-PCB ephezulu, izimbobo ezibonakala zilula zivame ukuletha imiphumela emibi emibi ekwakhiweni komjikelezo. Ukuze unciphise imiphumela emibi ebangelwa umphumela we-parasitic womgodi, umklamo ungaba ngangokunokwenzeka:
Kusuka ezintweni ezimbili zezindleko nekhwalithi yesiginali, khetha usayizi ofanele wosayizi we-via. Uma kunesidingo, ungacabanga ngokusebenzisa usayizi ohlukile we-vias, onjalo wokuhlinzekwa kwamandla noma izimbobo zocingo zomhlaba, ungacabanga ukusebenzisa usayizi omkhulu ukunciphisa ubugebengu, kanye ne-signal wiring, ungasebenzisa okuncane nge. Vele, njengoba usayizi we-Via uyancipha, izindleko ezihambisanayo zizokhuphuka
Amafomula womabili okuxoxwe ngawo angenhla angaphethwa ngokuthi ukusetshenziswa kwebhodi le-PCB elincanyana kuyasiza ekunciphiseni amapharamitha amabili e-parasitic e-via
I-wiring yesiginali ebhodini le-PCB akufanele liguqulwe ngangokunokwenzeka, okusho ukuthi, zama ukungasebenzisi vias okungadingekile.
UVias kumele abizwe kwizikhonkwane zokunikezwa kwamandla nangomhlaba. Okufushane ukuhola phakathi kwezikhonkwane kanye ne-vias, okungcono. Izimbobo eziningi zingakhiwa ngokufana ukuze zinciphise ukufakwa okufanayo.
Beka ezinye izimbobo eziseduze nezimbobo zoshintsho lwesiginali ukuze zinikeze i-loop eseduze yesiginali. Ungafaka ngisho nezimbobo zomhlaba wonke ebhodini le-PCB.
Ngamabhodi we-PCB aphezulu aphezulu anobukhulu obuphezulu, ungacabanga ngokusebenzisa izimbobo ezincane.
