Ukubhoboza Okujulile Okulawulwayo Ekukhiqizweni kwe-PCB: Ukubhoboza Emuva kuyini ukubhoboza emuva ku-pcb?
Ukubhoboza emuva emabhodini okuxhumanisa aphrintiwe anezingqimba eziningi kuyinqubo yokususa i-stub ukuze kukhiqizwe ama-via, okuvumela izimpawu ukuthi zisuke kungqimba olulodwa lwebhodi ziye kolunye. (Ama-stub azodala ukubonakaliswa, ukuhlakazeka, ukubambezeleka, nezinye izinkinga ngesikhathi sokudluliselwa kwesignali, okuzobangela ukuthi isignali iphazanyiswe.) Ukubhoboza ekujuleni okulawulwayo kudinga ikhono eliyinkimbinkimbi. Ukwenza amabhodi wesekethe anezingqimba eziningi, amabhodi anezingqimba ezingu-12, kudinga ukuxhuma ungqimba lokuqala nengqimba yesishiyagalolunye. Ngokuvamile, sibhoboza imigodi kanye kuphela ngaphambi kokufaka ama-via. Isitezi sokuqala nesitezi se-12 ngakho-ke zixhunywe ngokushesha. Eqinisweni, isitezi sokuqala sidinga nje ukuxhunywa esitezi sesishiyagalolunye. Njengoba kungekho zintambo ezixhumanisa amazinga e-10 kuya kwele-12, zifana nezinsika. Le kholomu inomthelela endleleni yesignali futhi ingase yonakalise ubuqotho besignali yokuxhumana. Ngakho-ke, imbobo yesibili yabhobozwa ohlangothini oluphambene lwekholomu eyengeziwe (ebizwa ngokuthi i-STUB embonini).
Ngenxa yalokho, yaziwa ngokuthi ukubhoboza ngemuva, nokho ngokuvamile akuhlanzekile kangako njengokubhoboza ngoba isinyathelo esilandelayo sizofaka ithusi nge-electrolyze futhi isihloko sokubhoboza naso sibukhali. Ngakho-ke sizoshiya iphuzu elincane kakhulu; ubude balesi STUB esisele baziwa ngokuthi inani le-B, futhi ngokuvamile lisukela ku-50 kuya ku-150 UM.
Ubuchwepheshe be-PCB bokubhoboza emuva
Ngenxa yesidingo sokunciphisa ukulahleka kwesignali kwezinhlelo zokusebenza ezivame kakhulu, kudingeka imbobo edlulayo exhumanisa izendlalelo ukuze isignali igeleze njengoba isuka kwenye iye kwenye. Kunconywa ukususa ithusi elisele kulo mbobo kulolu hlelo lokusebenza ngoba lisebenza njenge-antenna futhi lithinta ukudluliswa uma isignali izogeleza isuka kungqimba lokuqala iye kungqimba lwesibili ebhodini lezingqimba ezingama-20, isibonelo.
Ukuze sithole ukuzinza okukhulu kwesignali, sibhoboza ithusi "eliningi" emgodini sisebenzisa ukubhoboza emuva (ukujula okulawulwayo ku-z-axis). Umphumela ofanele ukuthi i-stub (noma ithusi "eliningi") ibe mfushane ngangokunokwenzeka. Ngokuvamile, usayizi wokubhoboza emuva kufanele ube mkhulu ngo-0.2mm kune-via ehambisanayo.
Iinqubo yokudonsa emuva isusa izingcezukusuka ezimbotsheni ezimbozwe ngepulasitiki (ama-via). Izinti azidingeki /izingxenye ezingasetshenziswanga zama-via, ezinwebeka ngaphezu kwesendlalelo sangaphakathi esixhunyiwe sokugcina.
Izicucu zingaholelaukuzindla, kanye neukuphazamiseka komthamo, ukungasebenzi kanye nokuphazamiseka. La maphutha okungaqhubeki aba bucayi ngokwandisa isivinini sokusabalala.
Izindiza zasemuvakanye namaBhodi Esifunda Aphrintiwe aminyene ikakhulukazi, angahlala isikhathi esideukuphazamiseka okukhulu kobuqotho besiginalingokusebenzisa izinti. Ngoba Ama-PCB Avame Ukuba Ngcono(isb. ngokulawula i-Impedance), ukusetshenziswa kwe-backdrilling, kanye nokusetshenziswa kwe-izindwangu ezingaboni futhi ezingcwatshwe, kungaba yingxenye yesisombululo.
I-Backdrill ingasetshenziswa ku-noma yiluphi uhlobo lwebhodi lesifundalapho izinti zibangela ukuwohloka kobuqotho besignali, ngokucabangela okuncane kokuklama kanye nokwakheka. Ngokuphambene nalokho, uma usebenzisa ama-blind vias, isilinganiso sesici kufanele sikhunjulwe.
Izici zokubhoboza emuva kwe-PCB
Izinzuzo Zokubhoboza Emuva
● Nciphisa ukuphazamiseka komsindo kanye nokujikijela okuqondile;
● Thuthukisa ubuqotho besiginali;
● Ukunciphisa ukujiya kwendawo;
● Nciphisa ukusetshenziswa kwama-vias afihliwe futhi angaboni futhi unciphise ubunzima bokukhiqizwa kwe-PCB;
● Izinga lamaphutha ebhithi eliphansi (BER);
● Ukunciphisa isignali kancane ngokuqhathanisa okuthuthukisiwe kwe-impedance;
● Umthelela omncane womklamo kanye nokwakheka;
● Ububanzi be-bandwidth yesiteshi obukhuphukile;
● Amanani edatha akhuphukile;
● ukwehla kokukhishwa kwe-EMI/EMC okuvela ekugcineni kwe-stub;
● Ukunciphisa ukucasuka kwamamodi okuzwakala kwe-resonance;
● Ukukhuluma okuncishisiwe nge-crosstalk;
● Izindleko eziphansi kunezingqimba ezilandelanayo.
Ububi Bokubhoboza Emuva
Izimpawu eziphakeme zivame ukuba nezinkinga ezingase zihlotshaniswe nokusetshenziswa okunganele ngama-stubs. Ake sibheke ngokucophelela ezinye zezinkinga ngama-stubs.
I-Jitter Deterministic:
Womabili la mawashi ayisikhathi, futhi inani lephutha lesikhathi libizwa ngokuthi i-jitter. I-jetter yokuvimbela yilokho okwaziwa ngokuthi ukuguqulwa kwesikhashana okuvamile (okungukuthi, okulinganiselwe).
Ukunciphisa isignali:
Uma umsindo uncipha, ukuqina kwawo kuyancipha futhi ukushaya kwenhliziyo kuba buthakathaka.
Imisebe evela ku-EMI:
I-stub edlulayo ingasetshenziswa njenge-antenna, ikhipha i-EMI ekhanyayo.
Izici ezijwayelekile
● Ngokuvamile amabhodi aqinile ngemuva;
● Ngokuvamile kusetshenziswa ezingqimbeni ezingu-8 noma ngaphezulu;
● Ubukhulu bebhodi bungaphezu kuka-2.5mm;
● Usayizi omncane wokubamba ngu-0.3mm;
● I-Backdrill inkulu ngo-0.2mm kune-vias;
● Ukubekezelela ukujula kwe-backdrill+/-0.05MM.
Hlobo luni lwe-PCB oludinga ukubhobozwa emuva?
Ngokuvamile, imigodi yebhodi le-PCB ibholwa ebhodini (kusukela phezulu kuya phansi). Uma umkhondo oxhumanisa imigodi nge-via useduze nesendlalelo esiphezulu (noma isendlalelo esingezansi), kuzoholela ekuqhekekeni kwe-stub emgodini nge-via wesixhumanisi sokuxhumana kwe-PCB, okuzothinta ikhwalithi yesignali futhi kubangele ukubonakaliswa. Izimpawu ezihamba ngesivinini esisheshayo zithinteka kakhulu yilo mphumela.
Ukuze kutholakale ikhwalithi ephezulu yokudluliselwa kwesignali, ngokuvamile kuyaqondakala ukuthi ithrekhi yesekethe ebhodini le-PCB enezimpawu zayo ngesivinini esingaba yi-1Gbps idinga ukubhekwa njengokuhlanganisa ukwakheka kwe-back-drill. Yiqiniso, ukuklama imigqa yokuxhumana yesivinini esikhulu kudinga ubunjiniyela besistimu futhi akulula njengoba kungase kubonakale. Uma izixhumanisi zokuxhumanisa uhlelo zingeside kakhulu noma ikhono lokushayela le-chip liqinile ngokwanele, ikhwalithi yesignali ingase ingabi naphutha ngaphandle kokubhoboza emuva. Ngakho-ke, ukulingisa isixhumanisi sokuxhumanisa uhlelo kuyindlela enembile kakhulu yokunquma ukuthi i-back-drill iyadingeka noma cha.
Ungase wazi ukuthi, ngaphezu kokusebenzisa ubuchwepheshe bokubhoboza ngemuva, izindlela ezahlukene zokwakha zingasetshenziswa ukunciphisa noma ukwenza ngcono ubude be-stub. Lokhu kufaka phakathi amalungiselelo ahlukene okuhlanganisa, lapho imikhondo yesekethe idluliselwa khona ezingqimbeni eziseduze nokuphela kwe-stub, imigodi ye-vias ebhobozwe nge-laser (microvias), noma i-vias ezingaboni futhi ezifihliwe. Ngaphezu kwalokho, njengoba ezinye izindlela zisetshenziswa ukunciphisa ukubonakaliswa kwesignali kumabhodi anemvamisa ephezulu (aphakeme kune-3GHz), ukubhoboza ngemuva akudingeki.
Kodwa-ke, lezi zindlela azisebenzi ngaso sonke isikhathi esikhungweni sokukhiqiza futhi azibizi kakhulu ukunciphisa ukulahleka kwesiginali kuma-PCB amaningi anabantu abaningi noma ama-backplanes/ama-mid-planes. Ngakho-ke, okuwukuphela kwesinqumo esisebenzayo ukubhoboza i-via stub ngemuva. Uma imigodi ye-vias engaboni ingeyona inketho, ukubhoboza i-back kuba yinto ebalulekile kumabhodi avame kakhulu (ngaphezu kwe-1GHz ngaphakathi kwe-3GHz).
Futhi njengoba i-PCB inezingqimba eziningi kangaka, eminye imigodi ayikwazi ukwakheka njengemigodi engaboni (isibonelo, ku-PCB enezingqimba ezingu-16, eminye ngemigodi kumele ixhunywe ezingqimbeni 1 kuya ku-10 kanti enye ngembobo kumele ixhunywe ezingqimbeni 7 kuya ku-16; lo mklamo awufanele imigodi engaboni kodwa ufanele ukubhobozwa ngemuva).
Ungayenza kanjani i-PCB back drilling?
Inqubo Yokubhoboza Emuva
1. Ukuze uthole umgodi wokuqala wokubhoboza, sebenzisa umgodi wokubeka endaweni ku-PCB enikeziwe.
2. Ngaphambi kokufaka i-plating, sebenzisa i-membrane eyomile ukuvala imbobo yesikhundla.
3. Fafaza umgodi ngethusi ukuze udale isekethe yokuqondisa.
4. Dala isithombe sangaphandle ku-PCB.
5. Ngemva kokudala iphethini yesendlalelo sangaphandle, ibhodi lesithombe lizosetshenziswa kwi-PCB. Ngaphambi kwale nqubo, kubalulekile ukuvala imbobo yokubeka nge-membrane eyomile ngaphambi kokuqala le nqubo.
6.Sebenzisa izimbobo zokubeka zokubhoboza zokuqala ukuze uqondise ukubhoboza kwangemuva, bese usebenzisa i-drill bit ukubhoboza izimbobo ezifakwe ngogesi ezidinga le nqubo.
7. Ngemva kokubhoboza kokugcina, ibhodi idinga ukuhlanzwa ukuze kususwe noma yikuphi ukubhoboza okusele okungenzeka
8. Ngemva kokuba ibhodi seliqinisekisiwe futhi ubuqotho besiginali buthuthukisiwe, qaphela ukuthi umsebenzi wokubhoboza wenziwa ngendlela efanele yini.
Hlola ama-Back Drills
Uma umzila usuqediwe, kumele siqinisekise ukuthi ama-drill angemuva asethwe kahle. Ukuze uqinisekise lokhu, vula zonke izendlalelo. Uzobona ukuthi umugqa we-vias unemibala emibili kuwo. Ungqimba lokuqala noma lokuqala luboniswa ngombala obomvu, kanti ungqimba lokugcina luboniswa ngombala oluhlaza okwesibhakabhaka. Kulula ukuhlukanisa ama-vias abholwe ngemuva kwamanye ama-vias. Ama-vias abholwe ngemuva kuphela abonakala ngemibala emibili.
Chofoza i-Drill Table ngemuva kokukhetha indawo kumenyu enkulu ukuze uthole ukuthi zingaki i-Vias, i-PTH, kanye nezinye i-troll ezenziwe.
Ubunzima bobuchwepheshe benqubo yokubhoboza ngemuva.
1.Ukulawula ukujula kokumba ngemuva
Ukuze kucutshungulwe kahle ama-vias angaboni, ukulawula ukujula kokubhoboza ngemuva kubalulekile. Ukubekezelela ukujula kokubhoboza ngemuva kuthonywa kakhulu ukunemba kwemishini yokubhoboza ngemuva kanye nokubekezelela ukujiya okuphakathi. Nokho, ukunemba kokubhoboza ngemuva kungathinteka yizinto ezingaphandle ezifana nokumelana nokubhoboza, i-engeli yesihloko sokubhoboza, umphumela wokuxhumana phakathi kwebhodi lesembozo nedivayisi yokulinganisa, kanye ne-warpage yebhodi. Ukuze uthole imiphumela emihle kakhulu futhi uphathe ukunemba kokubhoboza ngemuva, kubalulekile ukukhetha izinto zokubhoboza ezifanele kanye namasu ngesikhathi sokukhiqiza. Abaklami bangaqinisekisa ukudluliswa kwesignali esezingeni eliphezulu futhi bagweme izinkinga zobuqotho besignali ngokuphatha ngokucophelela ukujula kokubhoboza ngemuva.
2. Ukulawula ukunemba kokubhoboza emuva
Ukulawula ukubhoboza okunembile ngemuva kubalulekile ekulawulweni kwekhwalithi ye-PCB ezinqubweni ezilandelayo. Ukubhoboza ngemuva kuhilela ukubhoboza kwesibili ngokusekelwe kububanzi bomgodi wokubhoboza kokuqala, futhi ukunemba kokubhoboza kwesibili kubalulekile. Ukunemba kokuhlangana kokubhoboza kwesibili kungathinteka yizinto eziningana eziguquguqukayo, njengokwandiswa kwebhodi nokufinyela, ukunemba komshini, kanye namasu okubhoboza. Kubalulekile ukuqinisekisa ukuthi inqubo yokubhoboza ngemuva ilawulwa ngokunembile ukubhoboza ukuze kuncishiswe amaphutha futhi kugcinwe ukudluliselwa kwesignali kanye nobuqotho obufanele.
Isinyathelo esibaluleke kakhulu nesiyinselele ukubhoboza ngoba ngisho nephutha elincane lingabangela umonakalo omkhulu. Ngaphambi kokufaka i-oda, kufanele ucabangele amakhono omenzi we-PCB. I-Richfulljoy inikeza amabhodi abhoboziwe emuva ngamanani angabizi futhi igxile ekuhlanganisweni kwe-PCB prototype. Izinzuzo zethu zifaka phakathi izikhathi zokulethwa okusheshayo kanye nokuthembeka okuphezulu. I-Richfulljoy, umenzi we-PCB owaziwayo eShayina, inalo lonke ulwazi namakhono adingekayo ukukusiza. Uma uneziphakamiso zokuhlanganiswa kwe-PCB noma i-prototype, sicela uxhumane nathi ku-: mkt-2@rich-pcb.com
