PCB (Printed Circuit Board), igama lesiShayina liyibhodi lesifunda eliphrintiwe, elaziwa nangokuthi ibhodi lesifunda eliphrintiwe, liyingxenye ebalulekile ye-elekthronikhi, isekela izingxenye ze-elekthronikhi, kanye nesithwali sokuxhunywa kukagesi kwezingxenye ze-elekthronikhi.Ngenxa yokuthi yenziwa kusetshenziswa ukuphrinta kwe-elekthronikhi, ibizwa ngokuthi ibhodi lesifunda "eliphrintiwe".
1. Ungakhetha kanjani ibhodi le-PCB?
Ukukhethwa kwebhodi le-PCB kufanele kube nebhalansi phakathi kwezidingo zokuhlangana, ukukhiqizwa ngobuningi kanye nezindleko.Izidingo zokuklama ziqukethe kokubili izingxenye zikagesi nezemishini.Ngokuvamile le nkinga yezinto ezibonakalayo ibaluleke kakhulu lapho uklama amabhodi e-PCB anesivinini esikhulu (imvamisa enkulu kune-GHz).
Isibonelo, okokusebenza kwe-FR-4 okuvame ukusetshenziswa namuhla kungase kungafaneleki ngoba ukulahlekelwa kwe-dielectric ngemvamisa yama-GHz ambalwa kuzoba nomthelela omkhulu ekuncipheni kwesignali.Ngokuphathelene nogesi, kuyadingeka ukunaka ukuthi i-dielectric constant (dielectric constant) kanye nokulahlekelwa kwe-dielectric kufanelekile imvamisa eklanyelwe.
2. Ungakugwema kanjani ukuphazamiseka kwefrikhwensi ephezulu?
Umqondo oyisisekelo wokugwema ukuphazamiseka kwemvamisa ephezulu ukunciphisa ukuphazamiseka kwezinkundla ze-electromagnetic signal frequency, okuyilokho okubizwa nge-crosstalk (Crosstalk).Ungakwazi ukwandisa ibanga phakathi kwesiginali yesivinini esikhulu kanye nesiginali ye-analog, noma wengeze imikhondo yokuqapha/i-shunt eduze kwesiginali ye-analog.Futhi qaphela ukuphazamiseka komsindo we-digital ground emhlabathini we-analog.
3. Ngomklamo wesivinini esikhulu, ungayixazulula kanjani inkinga yesignali yobuqotho?
Ubuqotho besignali ngokuyisisekelo kuyindaba yokufanisa okungenakuqhathaniswa.Izinto ezithinta ukufaniswa kwe-impedance zifaka ukwakheka nokukhinyabezeka kokuphumayo komthombo wesignali, isici esivimbelayo sokulandela umkhondo, izici zesiphetho somthwalo, kanye ne-topology yokulandela umkhondo.Isixazululo siwukuthembela ekunqanyulweni nasekulungiseni i-topology yezintambo.
4. Itholakala kanjani indlela yokusabalalisa umehluko?
Kunamaphuzu amabili okufanele uwanake ku-wiring ye-different pair.Enye iwukuthi ubude bemigqa emibili kufanele bube bude ngangokunokwenzeka.Kunezindlela ezimbili ezihambisanayo, enye iwukuthi imigqa emibili igijima ungqimba olufanayo lwezintambo (eceleni-ne-side), kanti enye iwukuthi imigqa emibili igijima phezu kwezingqimba eziseduze ezingenhla neziphansi (ngaphezulu-ngaphansi).Ngokuvamile, i-side-by-side (ihlangothi ngehlangothini, ihlangene) isetshenziswa ngezindlela eziningi.
5. Ngomugqa wesiginali yewashi onetheminali eyodwa kuphela yokuphumayo, ungayisebenzisa kanjani izintambo ezihlukanisayo?
Ukusebenzisa izintambo ezihlukanisayo, kunengqondo kuphela ukuthi umthombo wesignali nomamukeli kokubili amasignali ahlukene.Ngakho-ke akwenzeki ukusebenzisa izintambo ezihlukanisayo zesignali yewashi enokukhishwa okukodwa kuphela.
6. Ingabe i-resistor ehambisanayo ingezwa phakathi kwamapheya emigqa ehlukene ekugcineni kokwamukela?
Ukumelana okufanayo phakathi kwamapheya emigqa ehlukile ekugcineni kokwamukela kuvame ukungezwa, futhi inani layo kufanele lilingane nenani le-impedance ehlukile.Ngale ndlela ikhwalithi yesiginali izoba ngcono.
7. Kungani izintambo zamapheya ahlukene kufanele zisondele futhi zihambisane?
Umzila wamapheya ahlukene kufanele usondele kahle futhi uhambisane.Okubizwa ngokuthi ukusondelana okufanele kungenxa yokuthi ibanga lizothinta inani le-impedance ehlukile, okuyipharamitha ebalulekile yokuklama ipheya ehlukile.Isidingo sokufana singenxa yesidingo sokugcina ukuhambisana kwe-impedance ehlukile.Uma imigqa emibili ikude noma iseduze, i-impedance ehlukile izobe ingahambisani, okuzothinta ubuqotho besignali (ubuqotho besignali) kanye nokulibaziseka kwesikhathi (ukubambezeleka kwesikhathi).
8. Ungabhekana kanjani nokungqubuzana kwethiyori kuzintambo zangempela
Ngokuyisisekelo, kulungile ukuhlukanisa umhlabathi we-analog/digital.Kufanele kuqashelwe ukuthi ukulandelelwa kwesignali akufanele kweqe indawo ehlukanisiwe (i-moat) ngangokunokwenzeka, futhi indlela yamanje yokubuya (indlela yamanje ebuyayo) yokunikezwa kwamandla kanye nesignali akufanele ibe kukhulu kakhulu.
I-crystal oscillator i-analog positive feedback oscillation circuit.Ukuze ibe nesiginali ye-oscillation ezinzile, kufanele ihlangabezane nezicaciso zokuzuza kweluphu nesigaba.Kodwa-ke, ukucaciswa kwe-oscillation kwalesi siginali ye-analog kuphazamiseka kalula, futhi ngisho nokwengeza imikhondo yokuqapha komhlaba kungase kungakwazi ukuhlukanisa ngokuphelele ukuphazamiseka.Futhi uma ikude kakhulu, umsindo endizeni yaphansi uzophinde uthinte i-positive oscillation circuit.Ngakho-ke, ibanga eliphakathi kwe-crystal oscillator ne-chip kumele libe seduze ngangokunokwenzeka.
Ngempela, kukhona ukungqubuzana okuningi phakathi kwezidingo ze-EMI ezihamba ngesivinini esiphezulu kanye ne-EMI.Kodwa isimiso esiyisisekelo siwukuthi izinto eziphikisayo nama-capacitor noma ubuhlalu be-ferrite obungezwe ngenxa ye-EMI azikwazi ukubangela izici ezithile zikagesi zesiginali ukuthi zehluleke ukuhlangabezana nezicaciso.Ngakho-ke, kungcono kakhulu ukusebenzisa amasu okuhlela izintambo kanye nokunqwabelanisa kwe-PCB ukuze uxazulule noma unciphise izinkinga ze-EMI, njengokuhambisa amasiginali anesivinini esiphezulu kungqimba lwangaphakathi.Okokugcina, sebenzisa i-resistor capacitor noma i-ferrite bead ukuze unciphise umonakalo esignali.
9. Indlela yokuxazulula ukungqubuzana phakathi kwe-wiring manual kanye ne-wiring ezenzakalelayo yamasignali anesivinini?
Iningi lamarutha azenzakalelayo esoftware yomzila enamandla manje asebeke imingcele yokulawula indlela yomzila kanye nenani lama-vias.Izinto zokusethwa zamakhono enjini ephendukayo kanye nezimo ezicindezelayo zezinkampani ezahlukahlukene ze-EDA kwesinye isikhathi zihluka kakhulu.
Isibonelo, ingabe kunezingqinamba ezanele zokulawula indlela izinyoka zenyoka, ingabe izikhala zamapheya ahlukene zingalawulwa, njalonjalo.Lokhu kuzothinta ukuthi indlela yomzila etholwe wumzila ozenzakalelayo ingahlangabezana yini nombono womklami.
Ngaphezu kwalokho, ubunzima bokulungisa i-wiring ngesandla bubuye bube nobudlelwane obuphelele nekhono lenjini ephendukayo.Ngokwesibonelo, pushability of iminonjana, pushability of vias, ngisho pushability iminonjana yethusi, njll Ngakho-ke, ukukhetha umzila onamandla injini emazombezombe ikhambi.
10. Mayelana namakhuphoni okuhlola.
Ikhuphoni lokuhlola lisetshenziselwa ukukala ukuthi ingabe isici se-PCB ekhiqiziwe siyahlangabezana yini nezidingo zokuklama nge-TDR (Time Domain Reflectometer).Ngokuvamile, i-impedance okufanele ilawulwe inezimo ezimbili: umugqa owodwa kanye nepheya ehlukile.Ngakho-ke, ububanzi bomugqa kanye nesikhala somugqa (uma kunamapheya ahlukene) kukhuphoni yokuhlola kufanele kufane nemigqa okufanele ilawulwe.
Okubaluleke kakhulu ukuma kwephuzu eliphansi lapho kulinganiswa.Ukuze kuncishiswe inani le-inductance le-ground lead (umthofu ophansi), indawo lapho i-TDR probe (probe) isekelwe khona ngokuvamile iseduze kakhulu nendawo lapho isignali ikalwa khona (ithiphu ye-probe).Ngakho-ke, ibanga kanye nendlela phakathi kwephuzu lapho isignali ikalwa khona kukhuphoni lokuhlola kanye nephuzu eliphansi Ukufanisa uphenyo olusetshenzisiwe.
11. Ekwakhiweni kwe-PCB enesivinini esikhulu, indawo engenalutho yongqimba lwesignali ingambozwa ngethusi, kodwa kufanele lisatshalaliswe kanjani ithusi lezendlalelo zamasignali amaningi ekusekelweni nasekunikezeni amandla?
Ngokuvamile, ithusi eliningi endaweni engenalutho liphansi.Vele unake ibanga eliphakathi kwethusi kanye nomugqa wesignali lapho ufaka ithusi eduze komugqa wesignali wesivinini esikhulu, ngoba ithusi elifakiwe lizonciphisa ukuvinjelwa kwesici komkhondo kancane.Futhi qaphela ukuthi ungaphazamisi isici sezinye izendlalelo, njengasesakhiwo somugqa wemigqa emibili.
12. Ingabe kungenzeka ukusebenzisa imodeli yomugqa we-microstrip ukubala isici somugqa wesignali ngaphezu kwendiza yamandla?Ingabe isignali phakathi kwamandla nendiza yaphansi ingabalwa kusetshenziswa imodeli ye-stripline?
Yebo, kokubili indiza yamandla nendiza yaphansi kufanele kubhekwe njengezindiza eziyinkomba lapho kubalwa isici esivimbelayo.Isibonelo, ibhodi elinezingqimba ezine: isendlalelo esiphezulu-amandla isendlalelo-phansi isendlalelo-phansi.Ngalesi sikhathi, imodeli yesici se-impedance ye-top layer trace imodeli yomugqa we-microstrip enendiza yamandla njengendiza eyinkomba.
13. Ngokuvamile, ingabe ukukhiqizwa okuzenzakalelayo kwamaphoyinti okuhlola ngesofthiwe kumabhodi aphrintiwe aphezulu angahlangabezana nezidingo zokuhlola zokukhiqiza ngobuningi?
Ukuthi amaphoyinti okuhlola akhiqizwe ngokuzenzakalela isofthiwe ejwayelekile ayahlangabezana yini nezidingo zokuhlola kuncike ekutheni izicaciso zokwengeza izindawo zokuhlola ziyahlangabezana yini nezimfuneko zezinto zokuhlola.Ukwengeza, uma izintambo ziminyene kakhulu futhi ukucaciswa kokwengeza amaphuzu okuhlola kuqinile, kungase kungenzeki ukwengeza ngokuzenzakalelayo amaphuzu okuhlola engxenyeni ngayinye yomugqa.Yiqiniso, kuyadingeka ukugcwalisa mathupha ezindaweni ezizohlolwa.
14. Ingabe ukungeza amaphuzu okuhlola kuzothinta ikhwalithi yamasignali anesivinini esikhulu?
Ngokuqondene nokuthi izothinta ikhwalithi yesignali, kuncike endleleni yokwengeza amaphuzu okuhlola nokuthi isignali ishesha kangakanani.Ngokuyisisekelo, amaphuzu okuhlola engeziwe (angasebenzisi iphinikhodi ekhona nge-DIP noma njengamaphoyinti okuhlola) angase engezwe emugqeni noma akhishwe emugqeni.Owokuqala ulingana nokwengeza i-capacitor encane ku-inthanethi, kanti lena yakamuva igatsha elengeziwe.
Lezi zimo ezimbili zizothinta isiginali yesivinini esikhulu ngaphezulu noma ngaphansi, futhi izinga lokuthonya lihlobene nesivinini semvamisa yesiginali kanye nezinga lomkhawulo lesiginali (isilinganiso somphetho).Usayizi womthelela ungaziwa ngokulingisa.Empeleni, iphoyinti lokuhlola lincane, lingcono (Yebo, kufanele futhi lihlangabezane nezidingo zemishini yokuhlola).Igatsha lifushane, lingcono.
15. Ama-PCB amaningana enza uhlelo, kufanele zixhunywe kanjani izintambo eziphansi phakathi kwamabhodi?
Lapho isignali noma amandla phakathi kwamabhodi e-PCB ahlukahlukene exhunywe kwelinye, isibonelo, ibhodi A linamandla noma amasiginali athunyelwe ebhodini B, kufanele kube nenani elilinganayo lamanje eligeleza lisuka kungqimba lomhlaba libuyela ebhodini A (lokhu Kirchoff umthetho wamanje).
Okwamanje kulokhu kwakheka kuzothola indawo yokumelana okuncane ukugeleza emuva.Ngakho-ke, inani lezikhonkwane ezinikezwe endizeni yaphansi akufanele libe lincane kakhulu ku-interface ngayinye, kungakhathaliseki ukuthi ukunikezwa kwamandla noma isignali, ukuze kuncishiswe i-impedance, enganciphisa umsindo endizeni yaphansi.
Ngaphezu kwalokho, kungenzeka futhi ukuhlaziya yonke loop yamanje, ikakhulukazi ingxenye ene-current enkulu, futhi ulungise indlela yokuxhuma yokwakheka noma ucingo lomhlabathi ukuze ulawule ukugeleza kwamanje (isibonelo, dala i-impedance ephansi endaweni ethile, ukuze ukugeleza okuningi kwamanje kusuka kulezi zindawo), nciphisa umthelela kwamanye amasiginali azwela kakhulu.
16. Ungakwazi yini ukwethula ezinye izincwadi zobuchwepheshe zakwamanye amazwe kanye nedatha yokuklama kwe-PCB enesivinini esikhulu?
Manje amasekhethi edijithali anesivinini esikhulu asetshenziswa emikhakheni ehlobene efana namanethiwekhi okuxhumana nezibali.Mayelana namanethiwekhi okuxhumana, imvamisa yokusebenza kwebhodi le-PCB isifinyelele ku-GHz, futhi inani lezendlalelo ezistakiwe lilingana nezingqimba ezingama-40 ngokwazi kwami.
Izinhlelo zokusebenza ezihlobene nesibali nazo zingenxa yokuthuthukiswa kwama-chip.Kungakhathaliseki ukuthi i-PC evamile noma iseva (Iseva), imvamisa yokusebenza ephezulu ebhodini nayo ifinyelele ku-400MHz (njenge-Rambus).
Ukusabela ezidingweni zendlela enesivinini esikhulu kanye nokuminyana okuphezulu, isidingo sama-vias angaboni/angcwatshwe, ama-mircrovia kanye nobuchwepheshe benqubo yokwakha siyakhula kancane kancane.Lezi zidingo zokuklama ziyatholakala ukuze kukhiqizwe ngobuningi ngabakhiqizi.
17. Amafomula amabili avame ukubhekwa njengesici:
Umugqa we-Microstrip (microstrip) Z={87/[sqrt(Er+1.41)]}ln[5.98H/(0.8W+T)] lapho u-W engububanzi bomugqa, u-T uwugqinsi lwethusi lokulandela umkhondo, futhi u-H ungu- Ibanga ukusuka kumkhondo ukuya endizeni eyireferensi, i-Er iwukungashintshi kwe-dielectric yezinto ze-PCB (i-dielectric constant).Le fomula ingasetshenziswa kuphela uma 0.1≤(W/H)≤2.0 kanye no-1≤(Er)≤15.
I-Stripline (stripline) Z=[60/sqrt(Er)]ln{4H/[0.67π(T+0.8W)]} lapho, H okuyibanga phakathi kwezindiza ezimbili eziyireferensi, futhi umkhondo utholakala phakathi nendawo izindiza ezimbili eziyisithenjwa .Le fomula ingasetshenziswa kuphela uma i-W/H≤0.35 ne-T/H≤0.25.
18. Ingabe ucingo oluphansi lungangezwa phakathi komugqa wesignali ohlukile?
Ngokuvamile, intambo yaphansi ayikwazi ukungezwa phakathi kwesignali yokuhlukanisa.Ngoba iphuzu elibaluleke kakhulu lesimiso sokusetshenziswa kwezimpawu zokuhlukanisa ukusebenzisa izinzuzo ezilethwa ukuhlanganisana (ukuhlanganisa) phakathi kwamasignali ahlukene, njengokukhanselwa kokugeleza, ukungavikeleki komsindo, njll. Uma ucingo oluphansi lwengezwa phakathi, umphumela wokuhlanganisa uzobhujiswa.
19. Ingabe i-rigid-flex board design idinga isofthiwe yokuklama ekhethekile kanye nokucaciswa?
Isekethe ephrintiwe eguquguqukayo (FPC) ingaklanywa ngesoftware ejwayelekile ye-PCB yokuklama.Futhi sebenzisa ifomethi ye-Gerber ukuze ukhiqizele abakhiqizi be-FPC.
20. Uyini umgomo wokukhetha kahle indawo okusekelwe kuyo i-PCB kanye necala?
Umgomo wokukhetha indawo ephansi ye-PCB kanye negobolondo ukusebenzisa umhlabathi we-chassis ukuze unikeze indlela ephansi ye-impedance yamanje yokubuyisela (imanje obuyayo) nokulawula indlela yamanje yokubuya.Isibonelo, imvamisa eduze kwedivayisi ye-high-frequency noma ijeneretha yewashi, ungqimba oluphansi lwe-PCB lungaxhunywa nomhlabathi we-chassis ngokulungisa izikulufu ukuze kuncishiswe indawo yayo yonke loop yamanje, ngaleyo ndlela kuncishiswe imisebe ye-electromagnetic.
21. Yiziphi izici okufanele siqale ngazo zebhodi lesifunda i-DEBUG?
Ngokuqondene namasekhethi edijithali, qala ngokunquma izinto ezintathu ngokulandelana:
1. Qinisekisa ukuthi wonke amanani okunikezwayo anosayizi womklamo.Amanye amasistimu anamandla amaningi angase adinge ukucaciswa okuthile kokuhleleka kanye nesivinini samandla athile.
2. Qinisekisa ukuthi wonke amaza esignali wewashi asebenza kahle futhi azikho izinkinga ezingezona eze-monotonic emaphethelweni esignali.
3. Qinisekisa ukuthi isignali yokusetha kabusha iyahlangabezana yini nezimfuneko zokucaciswa.Uma konke lokhu kujwayelekile, i-chip kufanele ithumele isignali yomjikelezo wokuqala (umjikelezo).Okulandelayo, lungisa iphutha ngokuya ngesimiso sokusebenza kwesistimu nephrothokholi yebhasi.
22. Uma usayizi webhodi lesifunda ulungisiwe, uma imisebenzi eminingi idinga ukufakwa ekwakhiweni, kuvame ukudingekile ukukhulisa ukuminyana komkhondo we-PCB, kodwa lokhu kungaholela ekuphazamisekeni okuthuthukisiwe kokulandelana kwemikhondo, futhi ngesikhathi esifanayo, iminonjana mincane kakhulu ukukhulisa impedance.Angeke yehliswe, sicela ochwepheshe bethule amakhono edizayini ye-PCB enesivinini esikhulu (≥100MHz) yokuminyana okuphezulu?
Uma udizayina ama-PCB anesivinini esikhulu nanokuminyana okuphezulu, ukuphazamiseka kwe-crosstalk kufanele kuqashelwe ngokukhethekile ngoba kunomthelela omkhulu kusikhathi nobuqotho besignali.
Nazi izinto ezimbalwa okufanele uzinake:
Lawula ukuqhubeka nokumataniswa kwesici se-trace impedance.
Usayizi wesikhala sokulandelela.Ngokuvamile, isikhala esivame ukubonakala siphinda kabili ububanzi bomugqa.Umthelela wesikhala sokulandelela ngesikhathi nobuqotho besignali ungaziwa ngokulingisa, futhi isikhala esincane esibekezeleleka singatholakala.Imiphumela ingahluka kusuka ku-chip kuye ku-chip.
Khetha indlela yokunqamula efanelekile.
Gwema indlela efanayo yokulandela izendlalelo ezingaphezulu neziphansi eziseduze, noma uze udlule imikhondo engenhla nengaphansi, ngoba lolu hlobo lwe-crosstalk lukhulu kunalolo lwamathrekhi aseduze ongqimba olufanayo.
Sebenzisa izimbobo ezingaboni/ezingcwatshiwe ukuze wandise indawo yokulandela umkhondo.Kodwa izindleko zokukhiqiza zebhodi le-PCB zizokhuphuka.Kunzima ngempela ukufeza ukufana okuphelele nobude obulinganayo ekusetshenzisweni kwangempela, kodwa kusadingeka ukukwenza ngangokunokwenzeka.
Ngaphezu kwalokho, ukunqanyulwa okuhlukile kanye nokunqanyulwa kwemodi evamile kungagodlwa ukuze kuncishiswe umthelela kusikhathi nobuqotho besignali.
23. Isihlungi kugesi we-analog sivame ukuba yisekethe ye-LC.Kodwa kungani ngezinye izikhathi i-LC ihlunga ngokuphumelelayo kune-RC?
Ukuqhathaniswa kwemiphumela yokuhlunga kwe-LC kanye ne-RC kufanele kucabangele ukuthi ibhendi yokuvama kufanele ihlungwe yini kanye nokukhethwa kwevelu ye-inductance kufanelekile.Ngoba ukusabela kwe-inductive (ukusabela) kwe-inductor kuhlobene nenani le-inductance kanye nemvamisa.
Uma imvamisa yomsindo wokunikezwa kwamandla iphansi futhi nevelu ye-inductance ingenkulu ngokwanele, umphumela wokuhlunga ungase ungabi muhle njenge-RC.Kodwa-ke, intengo okufanele uyikhokhe ngokusebenzisa ukuhlunga kwe-RC ukuthi isihlungi ngokwaso sichitha amandla, asisebenzi kahle, futhi sinake ukuthi i-resistor ekhethiwe ingaphatha amandla angakanani.
24. Iyiphi indlela yokukhetha i-inductance kanye nevelu ye-capacitance lapho uhlungwa?
Ngokungeziwe kumvamisa yomsindo ofuna ukuyihlunga, ukukhethwa kwevelu ye-inductance futhi kucabangela amandla okuphendula wamanje osheshayo.Uma i-terminal ephumayo ye-LC inethuba lokukhipha i-current enkulu khona manjalo, inani elikhulu kakhulu le-inductance lizothikameza isivinini samanje esikhulu esigeleza ku-inductor futhi likhulise umsindo ogelezayo.Inani le-capacitance lihlobene nosayizi wevelu yokucaciswa komsindo we-ripple ongabekezelelwa.
Isidingo senani lomsindo omncane we-ripple, inani le-capacitor likhulu.I-ESR/ESL ye-capacitor nayo izoba nomthelela.Ukwengeza, uma i-LC ibekwe ekuphumeni kwamandla okulawula ukushintsha, kuyadingeka futhi ukunaka umthelela we-pole/zero okhiqizwe yi-LC ekuzinzeni kweluphu yokulawula impendulo engalungile..
25. Ungahlangabezana kanjani nezidingo ze-EMC ngangokunokwenzeka ngaphandle kokubanga ingcindezi yezindleko ezinkulu?
Izindleko ezikhuphukile ngenxa ye-EMC ku-PCB ngokuvamile kungenxa yokwanda kwenani lezendlalelo zomhlabathi zokuthuthukisa umphumela wokuvikela kanye nokwengezwa kobuhlalu be-ferrite, ukuklinywa namanye amadivaysi okucindezela ama-harmonic ama-high-frequency.Ngaphezu kwalokho, ngokuvamile kuyadingeka ukubambisana nezinhlaka ezivikelayo kwezinye izindlela zokwenza lonke uhlelo ludlule izidingo ze-EMC.Okulandelayo ngamathiphu ambalwa wokuklama ibhodi le-PCB ukunciphisa umphumela wemisebe kagesi okhiqizwe isekethe.
Khetha idivayisi enezinga lokubulala elihamba kancane ngangokunokwenzeka ukuze unciphise izingxenye zefrikhwensi ephezulu ezikhiqizwe isignali.
Naka ukubekwa kwezingxenye zemvamisa ephezulu, hhayi eduze kakhulu nezixhumi zangaphandle.
Naka ukufaniswa kwe-impedance kwamasignali esivinini esikhulu, isendlalelo sezintambo kanye nendlela yamanje yokubuya (indlela yamanje yokubuyisela) ukunciphisa ukubonakaliswa kwe-high-frequency kanye nemisebe.
Beka ama-decoupling capacitor anele futhi afanele kumaphini wamandla wedivayisi ngayinye ukuze ulinganise umsindo emandleni nasezindizeni eziphansi.Naka ngokukhethekile ukuthi impendulo yemvamisa nezici zokushisa ze-capacitor ziyahlangabezana yini nezidingo zokuklama.
Umhlabathi oseduze nesixhumi sangaphandle ungahlukaniswa kahle kusukela ekubunjweni, futhi umhlabathi wesixhumi kufanele uxhunywe emhlabathini we-chassis oseduze.
Sebenzisa ngokufanelekile i-ground guard/shunt traces eduze kwamasignali anesivinini esikhulu.Kodwa naka umthelela wokulandela umkhondo we- guard/shunt on the impedance isici somkhondo.
Isendlalelo samandla singu-20H ngaphakathi kunokwakheka, futhi H ibanga phakathi kwesendlalelo samandla nokwakheka.
26. Uma kunamabhulokhi wokusebenza wedijithali/analogi amaningi ebhodini elilodwa le-PCB, inkambiso evamile ukuhlukanisa indawo yedijithali/ye-analogi.Siyini isizathu?
Isizathu sokuhlukanisa umhlabathi wedijithali/i-analogi ingoba isifunda sedijithali sizodala umsindo ekunikezeni amandla naphansi lapho sishintsha phakathi kwamandla aphezulu naphansi.Ubukhulu bomsindo buhlobene nesivinini sesignali kanye nobukhulu bamanje.Uma indiza ephansi ingahlukaniswanga futhi umsindo owenziwe yisifunda endaweni yedijithali mkhulu futhi isifunda endaweni ye-analog siseduze kakhulu, khona-ke ngisho noma amasignali edijithali ne-analog angaweli, isignali ye-analog isazophazanyiswa. ngomsindo waphansi.Okusho ukuthi, indlela yokungahlukanisi isisekelo sedijithali ne-analog ingasetshenziswa kuphela lapho indawo yesifunda se-analog ikude nendawo yesifunda sedijithali eyenza umsindo omkhulu.
27. Enye indlela iwukuqinisekisa ukuthi isakhiwo esihlukene sedijithali/i-analogi kanye nemigqa yesignali yedijithali/ye-analogi ayiphambani, ibhodi yonke ye-PCB ayihlukaniswanga, futhi indawo yedijithali/analogi ixhunywe kule ndiza yaphansi.Liyini iphuzu?
Isidingo sokuthi ukulandelela kwesignali ye-analog yedijithali angeke kuwele ingoba indlela yamanje ebuyayo (indlela yamanje yokubuyisela) yesiginali yedijithali eshesha kancane izozama ukugeleza ibuyele emthonjeni wesiginali yedijithali phansi eduze naphansi komkhondo.cross, umsindo owenziwe yi-current return uzovela endaweni yesifunda se-analog.
28. Icatshangwa kanjani inkinga yokufanisa i-impedance lapho uklama umdwebo wohlelo lomklamo we-PCB onesivinini esikhulu?
Lapho uklama amasekethe e-PCB anesivinini esikhulu, ukufaniswa kwe-impedance kungenye yezinto zokuklama.Inani le-impedance linobudlelwano obuphelele nendlela yomzila, njengokuhamba phezu kwesendlalelo esingaphezulu (i-microstrip) noma isendlalelo sangaphakathi (i-stripline/double stripline), ibanga ukusuka kusendlalelo sereferensi (ungqimba lwamandla noma ungqimba lomhlabathi), ukulandelela ububanzi, i-PCB Okubalulekile, njll. Kokubili kuzothinta inani lesici lokuvimbela umkhondo.
Okusho ukuthi, inani le-impedance linganqunywa kuphela ngemuva kwe-wiring.Isofthiwe yokulingisa evamile ngeke ikwazi ukucabangela ezinye izimo zezintambo ngokuvinjelwa okungaqhubeki ngenxa yomkhawulo wemodeli yomugqa noma i-algorithm yezibalo esetshenzisiwe.Ngalesi sikhathi, izinqamuli ezithile kuphela (izinqamuli), njengezinqamuli zochungechunge, ezingagcinwa kumdwebo wohlelo.ukunciphisa umthelela wokunqanyulwa kwe-impedance.Isixazululo sangempela esiyisisekelo senkinga ukuzama ukugwema ukungaqhubeki kwe-impedance lapho ufaka izintambo.
29. Ngingawunikeza kuphi umtapo wolwazi onembe kakhulu wemodeli ye-IBIS?
Ukunemba kwemodeli ye-IBIS kuthinta ngokuqondile imiphumela yokulingisa.Ngokuyisisekelo, i-IBIS ingathathwa njengedatha yesici sikagesi yesekethe elinganayo yebhafa ye-chip I/O, ngokuvamile engatholwa ngokuguqula imodeli ye-SPICE, futhi idatha ye-SPICE inobudlelwano obuphelele nokukhiqizwa kwe-chip, ngakho-ke. idivayisi efanayo inikezwa abakhiqizi be-chip abahlukene.Idatha eku-SPICE ihlukile, futhi idatha ekumodeli ye-IBIS eguquliwe nayo izohluka ngokufanele.
Okusho ukuthi, uma kusetshenziswe amadivaysi omkhiqizi A, kuphela anekhono lokuhlinzeka ngedatha yemodeli enembile yamadivayisi abo, ngoba akekho omunye owazi kangcono kunabo ukuthi iyiphi inqubo eyenziwa ngamadivaysi abo.Uma i-IBIS ehlinzekwe ngumkhiqizi ingalungile, okuwukuphela kwesixazululo ukucela njalo umenzi ukuthi athuthuke.
30. Lapho uklama ama-PCB anesivinini esikhulu, yiziphi izici okufanele abaklami bacabangele imithetho ye-EMC ne-EMI?
Ngokuvamile, idizayini ye-EMI/EMC idinga ukucabangela zombili izici ezikhazimulayo neziqhutshwayo.Eyangaphambili ingeyengxenye yefrikhwensi ephezulu (≥30MHz) bese eyakamuva ingeyengxenye engaphansi (≤30MHz).
Ngakho awukwazi ukunaka imvamisa ephezulu futhi ungayinaki ingxenye yefrikhwensi ephansi.Umklamo omuhle we-EMI/EMC kufanele ucabangele indawo yedivayisi, ukuhlelwa kwesitaki se-PCB, indlela yokuxhumana okubalulekile, ukukhethwa kwedivayisi, njll. ekuqaleni kwesakhiwo.Uma kungekho ilungiselelo elingcono kusengaphambili, lingaxazululwa ngemva kwalokho Izothola umphumela ophindwe kabili ngesigamu somzamo futhi yandise izindleko.
Isibonelo, indawo yejeneretha yewashi akufanele ibe seduze nesixhumi sangaphandle ngangokunokwenzeka, isignali yesivinini esikhulu kufanele iye kungqimba lwangaphakathi ngangokunokwenzeka futhi inake ukuqhubeka kokufanisa i-impedance yesici kanye ungqimba lwereferensi ukuze kuncishiswe ukubonakala, futhi umthambeka (izinga elibulalayo) lesignali ephushwa idivayisi kufanele ibe mncane ngokusemandleni ukuze unciphise ukuphakama. umsindo wendiza yamandla.
Ukwengeza, qaphela indlela yokubuya yesignali ye-high-frequency yamanje ukuze wenze indawo ye-loop ibencane ngangokunokwenzeka (okungukuthi, i-loop impedance incane ngangokunokwenzeka) ukunciphisa imisebe.Kungenzeka futhi ukulawula ububanzi bomsindo we-high-frequency ngokuhlukanisa ukwakheka.Ekugcineni, khetha kahle indawo okusekelwe kuyo i-PCB kanye nekesi (i-chassis ground).
31. Ungawakhetha kanjani amathuluzi e-EDA?
In the software pcb design yamanje, ukuhlaziywa ezishisayo akuyona iphuzu eliqinile, ngakho-ke akunconywa ukuyisebenzisa.Kweminye imisebenzi engu-1.3.4, ungakhetha i-PADS noma i-Cadence, futhi isilinganiso sokusebenza nenani sihle.Abaqalayo ekwakhiweni kwe-PLD bangasebenzisa indawo ehlanganisiwe enikezwe abakhiqizi be-chip be-PLD, futhi amathuluzi wephuzu elilodwa angasetshenziswa lapho kuklanywa amasango angaphezu kwesigidi esisodwa.
32. Sicela uncome isofthiwe ye-EDA elungele ukucutshungulwa kwesiginali yesivinini esikhulu kanye nokudlulisa.
Ngomklamo ojwayelekile wesekethe, i-INNOVEDA's PADS yinhle kakhulu, futhi kukhona isoftware yokulingisa efanayo, futhi lolu hlobo lomklamo luvame ukubala u-70% wezinhlelo zokusebenza.Ngokuklama kwesifunda esinesivinini esikhulu, izifunda ezixubile ze-analog nedijithali, isisombululo se-Cadence kufanele sibe isofthiwe esebenza kangcono kanye nentengo.Yiqiniso, ukusebenza kwe-Mentor kusekuhle kakhulu, ikakhulukazi ukuphathwa kwenqubo yokuklama kufanele kube okungcono kakhulu.
33. Incazelo yencazelo yongqimba ngalunye lwebhodi le-PCB
I-Topoverlay —- igama ledivayisi esezingeni eliphezulu, ebizwa nangokuthi isikrini sikasilika esiphezulu noma inganekwane yengxenye ephezulu, njenge-R1 C5,
IC10.bottomoverlay–ngokufanayo izendlalelo eziningi—–Uma uklama ibhodi elinezingqimba ezi-4, ubeka iphedi yamahhala noma usebenzisa, ukuchaze ngokuthi i-multilay, khona-ke iphedi yalo izovela ngokuzenzakalelayo kuma-layers angu-4, uma kuphela Ukuchaza njengongqimba olungaphezulu, khona-ke iphedi layo lizovela kuphela ungqimba olungaphezulu.
34. Yiziphi izici okufanele zinakwe ekwakhiweni, umzila kanye nokuhlelwa kwama-PCB anemvamisa ephezulu ngaphezu kwe-2G?
Ama-PCB anefrikhwensi ephezulu ngaphezu kwe-2G ayingxenye yedizayini yamasekhethi efrikhwensi yomsakazo, futhi awekho ngaphakathi kobubanzi bengxoxo yomklamo wesekethe yedijithali enesivinini esikhulu.Isakhiwo kanye nomzila wesekethe ye-RF kufanele kucatshangelwe kanye nomdwebo wohlelo, ngoba ukwakheka kanye nomzila kuzodala imiphumela yokusabalalisa.
Ngaphezu kwalokho, amanye amadivaysi angenzi lutho ekwakhiweni kwesekethe ye-RF atholwa ngencazelo yepharamitha kanye necwecwe lethusi elimise okukhethekile.Ngakho-ke, amathuluzi e-EDA ayadingeka ukuhlinzeka ngamadivaysi e-parametric futhi ahlele i-foil yethusi emise okukhethekile.
Isiteshi se-Mentor's boardstation sinemojula yomklamo we-RF ozinikele ehlangabezana nalezi zidingo.Ngaphezu kwalokho, idizayini evamile yefrikhwensi yomsakazo idinga amathuluzi okuhlaziya amagagasi omsakazo akhethekile, edume kakhulu embonini i-eesoft ye-agilent, enokuxhumana okuhle namathuluzi e-Mentor.
35. Ngomklamo we-PCB wemvamisa ephezulu ngaphezu kwe-2G, yimiphi imithetho okufanele idizayini ye-microstrip iyilandele?
Ukuze kuklanywe imigqa ye-RF microstrip, kuyadingeka ukusebenzisa amathuluzi okuhlaziya insimu ye-3D ukuze kukhishwe amapharamitha womugqa wokudlulisela.Yonke imithetho kufanele icaciswe kuleli thuluzi lokukhipha inkambu.
36. Kwi-PCB enawo wonke amasignali edijithali, kunomthombo wewashi ongu-80MHz ebhodini.Ngaphezu kokusebenzisa i-wire mesh (isisekelo), hlobo luni lwesekhethi okufanele isetshenziselwe ukuvikela ukuze kuqinisekiswe ikhono lokushayela elanele?
Ukuqinisekisa ikhono lokushayela lewashi, akufanele libonakale ngokuvikela.Ngokuvamile, iwashi lisetshenziselwa ukushayela i-chip.Ukukhathazeka okuvamile mayelana nekhono lokushayela iwashi kubangelwa ukulayishwa kwamawashi amaningi.I-chip yomshayeli wewashi isetshenziselwa ukuguqula isignali yewashi eyodwa ibe amaningana, futhi uxhumano lwephoyinti ukuya ephuzwini luyamukelwa.Lapho ukhetha i-chip yomshayeli, ngaphezu kokuqinisekisa ukuthi ihambisana ngokuyisisekelo nomthwalo kanye nonqenqema lwesiginali luhlangabezana nezidingo (ngokuvamile, iwashi liwuphawu olusebenza kahle onqenqemeni), lapho kubalwa isikhathi sohlelo, ukubambezeleka kwewashi kumshayeli. chip kufanele kucatshangelwe.
37. Uma kusetshenziswa ibhodi lesignali yewashi elihlukile, hlobo luni lwesixhumi esibonakalayo esivame ukusetshenziswa ukuze kuqinisekiswe ukuthi ukudluliswa kwesignali yewashi kuthinteke kancane?
Uma isignali yewashi iba mfishane, umphumela wolayini wokudlulisela ube mncane.Ukusebenzisa ibhodi lesignali yewashi elihlukile kuzokwandisa ubude bomzila wesignali.Futhi ukunikezwa kwamandla okuphansi kwebhodi nakho kuyinkinga.Ngokudluliswa kwebanga elide, kunconywa ukusebenzisa amasignali ahlukene.Usayizi we-L ungahlangabezana nezidingo zomthamo wokushayela, kodwa iwashi lakho alisheshi kakhulu, akudingekile.
I-38, 27M, umugqa wewashi we-SDRAM (80M-90M), i-harmonics yesibili neyesithathu yale migqa yewashi isanda ku-VHF band, futhi ukuphazamiseka kukhulu kakhulu ngemva kokungena kwemvamisa ephezulu kusukela ekugcineni kokuthola.Ngaphezu kokufinyeza ubude bomugqa, yiziphi ezinye izindlela ezinhle?
Uma i-harmonic yesithathu inkulu futhi i-harmonic yesibili incane, kungase kube ngenxa yokuthi umjikelezo womsebenzi wesignali ungama-50%, ngoba kulokhu, isignali ayinakho ngisho ne-harmonics.Ngalesi sikhathi, kuyadingeka ukuguqula umjikelezo womsebenzi wesignali.Ngaphezu kwalokho, uma isignali yewashi ingaqondile, ukufanisa kochungechunge lwesiphetho somthombo ngokuvamile kuyasetshenziswa.Lokhu kucindezela ukuboniswa kwesibili ngaphandle kokuphazamisa izinga lomkhawulo wewashi.Inani elihambisanayo ekugcineni komthombo lingatholwa ngokusebenzisa ifomula esithombeni esingezansi.
39. Iyini i-topology yezintambo?
I-Topology, ezinye zibizwa nangokuthi i-routing order.Ngohlelo lwezintambo lwenethiwekhi exhunywe izimbobo eziningi.
40. Indlela yokulungisa i-topology ye-wiring ukuze uthuthukise ubuqotho besignali?
Lolu hlobo lokuqondisa kwesignali yenethiwekhi luyinkimbinkimbi kakhulu, ngoba kumasignali endlela eyodwa, yezindlela ezimbili, namasignali wamazinga ahlukene, i-topology inamathonya ahlukene, futhi kunzima ukusho ukuthi iyiphi i-topology enenzuzo kukhwalithi yesignali.Ngaphezu kwalokho, lapho wenza ukulingisa kwangaphambili, iyiphi i-topology okufanele isetshenziswe edingeka kakhulu konjiniyela, futhi idinga ukuqonda izimiso zesekethe, izinhlobo zamasignali, kanye nobunzima bezintambo.
41. Ungazinciphisa kanjani izinkinga ze-EMI ngokuhlela isitaki?
Okokuqala nje, i-EMI kufanele icatshangelwe ohlelweni, futhi i-PCB iyodwa ayikwazi ukuxazulula inkinga.Ku-EMI, ngicabanga ukuthi ukupakisha ikakhulukazi ukunikeza indlela emfushane yokubuyisela isignali, ukunciphisa indawo yokuhlanganisa, nokucindezela ukuphazamiseka kwemodi yokuhlukanisa.Ngaphezu kwalokho, ungqimba lwaphansi kanye nohlaka lwamandla kuhlanganiswe ngokuqinile, futhi isandiso sikhulu ngokufanelekile kunesendlalelo samandla, esihle ekucindezeleni ukuphazamiseka kwemodi evamile.
42. Kubekweni ithusi?
Ngokuvamile, kunezizathu eziningana zokubeka ithusi.
1. EMC.Emhlabathini wendawo enkulu noma ithusi elinikezwa amandla, lizodlala indima yokuvikela, futhi ezinye ezikhethekile, njenge-PGND, zizodlala indima yokuvikela.
2. Izidingo zenqubo ye-PCB.Ngokuvamile, ukuze kuqinisekiswe umphumela we-electroplating noma i-lamination ngaphandle kokuguqulwa, ithusi libekwe phezu kongqimba lwe-PCB ngezintambo ezincane.
3. Izidingo zobuqotho besignali, zinikeza amasignali edijithali yemvamisa ephezulu indlela ephelele yokubuya, futhi zinciphise izintambo zenethiwekhi ye-DC.Yiqiniso, kukhona nezizathu zokushisa ukushisa, ukufakwa kwedivayisi ekhethekile kudinga ukubeka ithusi, njalonjalo.
43. Kuhlelo, i-dsp ne-pld ifakiwe, yiziphi izinkinga okufanele zinakwe lapho kuxhunywa izintambo?
Bheka isilinganiso sezinga lesignali yakho nobude bezintambo.Uma ukubambezeleka kwesignali kulayini wokudlulisela kuqhathaniswa nesikhathi sonqenqema lokushintsha kwesignali, inkinga yesiginali yobuqotho kufanele icatshangelwe.Ngaphezu kwalokho, kuma-DSP amaningi, i-topology yewashi nesignali yedatha izophinde ithinte ikhwalithi yesiginali kanye nesikhathi, okudinga ukunakwa.
44. Ngaphezu kocingo lwethuluzi le-protel, akhona yini amanye amathuluzi amahle?
Ngokuqondene namathuluzi, ngaphezu kwe-PROTEL, kunamathuluzi amaningi okufaka izintambo, njenge-MENTOR's WG2000, EN2000 series kanye ne-powerpcb, i-Cadence's allegro, i-zuken's cadstar, i-cr5000, njll., ngalinye linamandla alo.
45. Iyini “indlela yesignali ebuyayo”?
Indlela yokubuya yesignali, okungukuthi, ukubuyisela okwamanje.Uma isignali yedijithali enesivinini esikhulu idluliswa, isignali igeleza isuka kumshayeli ngomugqa wokudlulisa we-PCB iye emlayishweni, bese umthwalo ubuyela ekugcineni komshayeli eduze nomhlabathi noma ukunikezwa kwamandla ngendlela emfushane kakhulu.
Lesi siginali yokubuyisela phansi noma ukunikezwa kwamandla kubizwa ngokuthi indlela yokubuya kwesignali.UDkt.Johnson uchaze encwadini yakhe ukuthi ukudluliswa kwesignali yemvamisa ephezulu empeleni kuyinqubo yokushaja i-dielectric capacitance ehlanganiswe phakathi kolayini wokudlulisela kanye nongqimba lwe-DC.Okuhlaziywa yi-SI yizici ze-electromagnetic zale ndawo ebiyelwe kanye nokuhlangana phakathi kwazo.
46. Ukwenziwa kanjani ukuhlaziya kwe-SI kuzixhumi?
Esicacisweni se-IBIS3.2, kunencazelo yemodeli yesixhumi.Ngokuvamile sebenzisa imodeli ye-EBD.Uma kuyibhodi elikhethekile, njengendiza engemuva, imodeli ye-SPICE iyadingeka.Ungasebenzisa futhi isoftware yokulingisa enamabhodi amaningi (HYPERLYNX noma IS_multiboard).Lapho wakha uhlelo lwamabhodi amaningi, faka imingcele yokusabalalisa yezixhumi, ngokuvamile ezitholakala kubhukwana lokuxhuma.Yiqiniso, le ndlela ngeke inembe ngokwanele, kodwa inqobo nje uma ingaphakathi kwebanga elamukelekayo.
47. Yiziphi izindlela zokuqeda?
Ukunqanyulwa (ukuphela), okwaziwa nangokuthi ukufanisa.Ngokujwayelekile, ngokwendawo yokufanisa, ihlukaniswe yaba ukufanisa ukuphela okusebenzayo nokumatanisa kwetheminali.Phakathi kwazo, ukufaniswa komthombo kuvame ukufanisa uchungechunge lwe-resistor, futhi ukufaniswa kwetheminali ngokuvamile kufana ngokuhambisanayo.Kunezindlela eziningi, ezihlanganisa ukudonsa kwe-resistor, ukudonsa phansi kwe-resistor, ukufanisa i-Thevenin, ukufanisa i-AC, kanye nokufanisa i-Schottky diode.
48. Yiziphi izici ezinquma indlela yokuqeda (ukufanisa)?
Indlela yokufanisa ngokuvamile inqunywa izici ze-BUFFER, izimo ze-topology, izinhlobo zeleveli nezindlela zokwahlulela, kanye nomjikelezo wesiginali kanye nokusetshenziswa kwamandla wesistimu nakho kufanele kucatshangelwe.
49. Iyini imithetho yendlela yokuqeda (ukufanisa)?
Inkinga ebaluleke kakhulu kumasekethe edijithali inkinga yesikhathi.Inhloso yokwengeza okufanayo ukuthuthukisa ikhwalithi yesiginali kanye nokuthola isignali enqumayo ngesikhathi sokwahlulela.Ukuze uthole amasignali asebenzayo ezingeni, ikhwalithi yesiginali izinzile ngaphansi kwesisekelo sokuqinisekisa ukusungulwa nokubamba isikhathi;kumasiginali abambezelekile asebenzayo, ngaphansi kwesisekelo sokuqinisekisa ukulibaziseka kwesignali ye-monotonicity, isivinini sokulibaziseka sokushintsha isignali sihlangabezana nezimfuneko.Kukhona okuthile okuhambisanayo encwadini yomkhiqizo ye-Mentor ICX.
Ngaphezu kwalokho, "i-High Speed Digital design incwadi yesandla ye-blackmagic" inesahluko esinikezelwe esikhumulweni, esichaza indima yokumatanisa ubuqotho besignali kusukela kumgomo wamagagasi kagesi, ongasetshenziselwa ireferensi.
50. Ngingakwazi ukusebenzisa imodeli ye-IBIS yedivayisi ukulingisa umsebenzi onengqondo wocingo?Uma kungenjalo, kungenziwa kanjani ukulingiswa kwezinga lebhodi kanye neleveli yesistimu yesekethe?
Amamodeli e-IBIS angamamodeli zeleveli yokuziphatha futhi awakwazi ukusetshenziselwa ukulingisa okusebenzayo.Ngokulinganisa okusebenzayo, amamodeli we-SPICE noma amanye amamodeli zeleveli yesakhiwo ayadingeka.
51. Ohlelweni lapho idijithali ne-analogi kuhlangana khona, kunezindlela ezimbili zokucubungula.Enye iwukuhlukanisa umhlabathi wedijithali endaweni ye-analog.Ubuhlalu buxhunyiwe, kodwa ukunikezwa kwamandla akuhlukanisiwe;okunye ukuthi ukunikezwa kwamandla we-analog namandla kagesi edijithali kuyahlukaniswa futhi kuxhunywe ne-FB, futhi umhlabathi uyindawo ebumbene.Ngingathanda ukubuza uMnu. Li, ukuthi ingabe umphumela walezi zindlela ezimbili uyafana?
Kufanele kushiwo ukuthi kuyafana ngomgomo.Ngoba amandla nomhlabathi kuyalingana namasiginali wemvamisa ephezulu.
Inhloso yokuhlukanisa phakathi kwezingxenye ze-analog nedijithali iwukunqanda ukuphazamiseka, ikakhulukazi ukuphazamiseka kwamasekhethi edijithali kumasekhethi e-analog.Kodwa-ke, ukuhlukaniswa kungase kubangele indlela yokubuyisela isignali engaphelele, okuthinta ikhwalithi yesiginali yesignali yedijithali futhi kuthinte ikhwalithi ye-EMC yohlelo.
Ngakho-ke, kungakhathaliseki ukuthi iyiphi indiza ehlukanisiwe, kuncike ekutheni indlela yokubuyisela isignali ikhulisiwe nokuthi isignali yokubuya iphazamisa kangakanani isignali yokusebenza evamile.Manje kukhona neminye imiklamo exubile, kungakhathaliseki ukuthi ukunikezwa kwamandla kanye nomhlabathi, lapho ubeka ngaphandle, hlukanisa ukwakheka kanye nezintambo ngokwengxenye yedijithali kanye nengxenye ye-analog ukuze ugweme amasignali awela izifunda.
52. Imithetho yezokuphepha: Yiziphi izincazelo eziqondile ze-FCC ne-EMC?
I-FCC: ikhomishana yokuxhumana yenhlangano yaseMelika Ikhomishini Yezokuxhumana
I-EMC: ukuhambisana kwe-electromagnetic electromagnetic comppatibility
I-FCC iyinhlangano yamazinga, i-EMC iyindinganiso.Kunezizathu ezihambisanayo, amazinga kanye nezindlela zokuhlola zokumenyezelwa kwamazinga.
53. Kuyini ukwahlukanisa okuhlukile?
Amasignali ahlukene, amanye awo abuye abizwe ngokuthi amasiginali ahlukene, asebenzisa amasiginali amabili afanayo, aphikisanayo ukuze adlulisele isiteshi esisodwa sedatha, futhi ancike emehlukweni wezinga lamasignali amabili ukuze ahlulele.Ukuze kuqinisekiswe ukuthi amasignali amabili ahambisana ngokuphelele, kufanele agcinwe ehambisana ngesikhathi sokufaka izintambo, futhi ububanzi bomugqa kanye nesikhala somugqa kuhlala kungashintshiwe.
54. Iyini isofthiwe yokulingisa ye-PCB?
Kunezinhlobo eziningi zokulingisa, i-high-speed digital circuit signal integrity analysis simulation (SI) isofthiwe esetshenziswa kakhulu i-icx, i-signalvision, i-hyperlynx, i-XTK, i-spectraquest, njll. Abanye futhi basebenzisa i-Hspice.
55. Isoftware yokulingisa ye-PCB ikwenza kanjani ukulingiswa kwe-LAYOUT?
Emijikelezweni yedijithali enesivinini esikhulu, ukuze kuthuthukiswe ikhwalithi yesignali futhi kuncishiswe ubunzima bezintambo, amabhodi anezingqimba eziningi ngokuvamile asetshenziselwa ukunikeza izendlalelo zamandla ezikhethekile nezingqimba zomhlabathi.
56. Ungabhekana kanjani nesakhiwo kanye nezintambo ukuqinisekisa ukuzinza kwamasignali ngaphezu kuka-50M
Isihluthulelo sezintambo zesignali yedijithali yesivinini esiphezulu ukunciphisa umthelela wemigqa yokudlulisela kwikhwalithi yesignali.Ngakho-ke, ukuhlelwa kwamasignali anesivinini esiphezulu ngaphezu kwe-100M kudinga ukuthi ukulandelelwa kwesignali kube kufushane ngangokunokwenzeka.Kumasekhethi edijithali, amasignali anesivinini esikhulu achazwa ngesikhathi sokulibaziseka kokukhuphuka kwesignali.Ngaphezu kwalokho, izinhlobo ezahlukene zezimpawu (ezifana ne-TTL, GTL, LVTTL) zinezindlela ezihlukene zokuqinisekisa ikhwalithi yesignali.
57. Ingxenye ye-RF yeyunithi yangaphandle, ingxenye yefrikhwensi emaphakathi, ngisho nengxenye yesekhethi yefrikhwensi ephansi eqapha iyunithi yangaphandle ngokuvamile zisetshenziswa ku-PCB efanayo.Yiziphi izimfuneko zezinto ze-PCB enjalo?Ungayivimba kanjani i-RF, IF kanye namasekethe aphansi ukuthi angaphazamisani?
I-Hybrid circuit design iyinkinga enkulu.Kunzima ukuba nesixazululo esiphelele.
Ngokuvamile, umjikelezo wefrikhwensi yomsakazo wendlaliwe futhi ufakwe izintambo njengebhodi elilodwa elizimele ohlelweni, futhi kukhona ngisho nesikhala esikhethekile sokuvikela.Ngaphezu kwalokho, isekethe ye-RF ivamise ukuba nohlangothi olulodwa noma olukabili, futhi isekethe ilula, konke okuwukunciphisa umthelela kumapharamitha wokusabalalisa wesekethe ye-RF futhi kuthuthukiswe ukungaguquguquki kohlelo lwe-RF.
Uma kuqhathaniswa nezinto ezijwayelekile ze-FR4, amabhodi esekethe e-RF avame ukusebenzisa ama-high-Q substrates.I-dielectric engaguquki yalesi sici incane kakhulu, i-capacitance esabalalisiwe yomugqa wokudlulisela incane, i-impedance iphezulu, futhi ukubambezeleka kokudluliselwa kwesignali kuncane.Ekwakhiweni kwesekethe ye-hybrid, nakuba i-RF kanye namasekhethi edijithali akhelwe ku-PCB efanayo, ngokuvamile ahlukaniswa abe indawo yesifunda se-RF kanye nendawo yesekethe yedijithali, endlalwe futhi ifakwe izintambo ngokuhlukana.Sebenzisa i-vias yomhlabathi namabhokisi okuvikela phakathi kwawo.
58. Okwengxenye ye-RF, ingxenye yefrikhwensi emaphakathi kanye nengxenye yesekethe ephansi isetshenziswa ku-PCB efanayo, isiphi isisombululo unaso?
Isofthiwe yokuklama isistimu yezinga lebhodi ye-Mentor, ngaphezu kwemisebenzi eyisisekelo yokuklama isekethe, nayo inemojula yomklamo we-RF ozinikele.Kumojula ye-RF schematic design, imodeli yedivayisi enepharamitha inikezwa, kanye nesixhumi esibonakalayo esiphindwe kabili esinokuhlaziywa kwesekethe ye-RF namathuluzi okulingisa afana ne-EESOFT anikeziwe;kumojula ye-RF LAYOUT, umsebenzi wokuhlela iphethini osetshenziswa ngokukhethekile ukwakheka kwesekethe ye-RF kanye nezintambo kunikezwa, futhi kukhona ne-The interface yezindlela ezimbili yokuhlaziya isekethe ye-RF namathuluzi okulingisa afana ne-EESOFT ingahlehlisa ilebula imiphumela yokuhlaziya kanye ukulingisa emuva kumdwebo wohlelo kanye ne-PCB.
Ngesikhathi esifanayo, ukusebenzisa umsebenzi wokuphatha umklamo wesofthiwe ye-Mentor, ukusetshenziswa kabusha kwedizayini, ukutholwa komklamo, nomklamo wokuhlanganyela kungabonakala kalula.Sheshisa kakhulu inqubo yokuklama isekethe ye-hybrid.Ibhodi likamakhalekhukhwini liwumklamo ojwayelekile wesekethe exubile, futhi abakhiqizi abaningi bemiklamo yomakhalekhukhwini abakhulu basebenzisa i-Mentor plus yeesoft ka-Angelon njengeplathifomu yokuklama.
59. Siyini isakhiwo somkhiqizo weMentor?
Amathuluzi we-PCB we-Mentor Graphics ahlanganisa uchungechunge lwe-WG (ngaphambilini eyayiyi-veribest) kanye nochungechunge lwe-Enterprise (boardstation).
60. Isofthiwe ye-Mentor's PCB design isekela kanjani i-BGA, i-PGA, i-COB namanye amaphakheji?
I-Mentor's autoactive RE, ethuthukiswe kusukela ekutholweni kwe-Veribest, iyirutha yokuqala yemboni engenagridi, noma iyiphi i-engeli.Njengoba sonke sazi, kuma-ball grid arrays, amadivaysi e-COB, ama-gridless, nanoma iyiphi i-engeli routers kuwukhiye wokuxazulula izinga lomzila.Ku-RE esebenzayo yakamuva, imisebenzi efana nokuphusha nge-vias, i-copper foil, REROUTE, njll. yengeziwe ukuze kube lula ukuyisebenzisa.Ngaphezu kwalokho, usekela umzila onesivinini esikhulu, okuhlanganisa umzila wesignali kanye nomzila wokubhanqa ohlukile onezidingo zokulibaziseka kwesikhathi.
61. Ngabe isoftware ye-Mentor's PCB design ikusingatha kanjani ukupheya kwemigqa ehlukile?
Ngemuva kokuthi isofthiwe ye-Mentor ichaze izici zepheya ehlukile, amapheya amabili ahlukene angahanjiswa ndawonye, futhi ububanzi bomugqa, isikhala nobude bokubhangqa okuhlukile kuqinisekisiwe ngokuqinile.Angahlukaniswa ngokuzenzakalelayo lapho ehlangabezana nezithiyo, futhi indlela ye-via ingakhethwa lapho kushintsha izingqimba.
62. Ebhodini le-PCB elinezingqimba ezingu-12, kunezingqimba ezintathu zokunikezwa kwamandla kagesi 2.2v, 3.3v, 5v, futhi ngayinye yalezi zinto ezintathu zamandla ikusendlalelo esisodwa.Indlela yokubhekana ne-ground wire?
Ngokuvamile, izinto ezintathu ezinikezwa amandla zihlelwa ngokulandelana esitezi sesithathu, okungcono ngekhwalithi yesignali.Ngoba mancane amathuba okuthi isignali izohlukaniswa ezingqimbeni zendiza.Ukuhlukaniswa kwezigaba kuyisici esibalulekile esithinta ikhwalithi yesignali ngokuvamile enganakwa isofthiwe yokulingisa.Ezindizeni zamandla nezindiza eziphansi, ilingana namasignali amaza aphezulu.Ngokwenza, ngaphezu kokucabangela ikhwalithi yesignali, ukuhlanganisa indiza yamandla (usebenzisa indiza yaphansi eseduze ukuze kuncishiswe i-AC impedance yendiza yamandla) kanye ne-symmetry yokupakisha yizo zonke izici ezidinga ukucatshangelwa.
63. Ungahlola kanjani ukuthi i-PCB iyahlangabezana yini nezidingo zenqubo yokuklama lapho iphuma efekthri?
Abakhiqizi abaningi be-PCB kufanele badlule ekuhloleni kokuqhubeka kwenethiwekhi amandla avuliwe ngaphambi kokuthi ukucubungula kwe-PCB kuqedwe ukuze kuqinisekiswe ukuthi konke ukuxhumana kulungile.Ngesikhathi esifanayo, abakhiqizi abaningi ngokwengeziwe basebenzisa ukuhlolwa kwe-x-ray ukuze bahlole amaphutha athile ngesikhathi sokucwiliswa noma ukucwiliswa.
Ebhodini eliqediwe ngemva kokucubungula isichibi, ukuhlolwa kokuhlolwa kwe-ICT ngokuvamile kusetshenziswa, okudinga ukungeza amaphuzu okuhlola e-ICT phakathi nomklamo we-PCB.Uma kunenkinga, umshini okhethekile wokuhlola i-X-ray nawo ungasetshenziswa ukuze kukhishwe ukuthi iphutha libangelwa ukucubungula.
64. Ingabe “ukuvikela umshini” kuwukuvikela kwebhokisi?
Yebo.I-casing kufanele iqine ngangokunokwenzeka, isebenzise izinto zokwakha ezincane noma ingabikho, futhi isekelwe phansi ngangokunokwenzeka.
65. Ingabe kuyadingeka ukucabangela inkinga ye-esd ye-chip ngokwayo lapho ukhetha i-chip?
Kungakhathaliseki ukuthi ibhodi elinezingqimba ezimbili noma ibhodi elinezingqimba eziningi, indawo yomhlabathi kufanele ikhuliswe ngangokunokwenzeka.Lapho ukhetha i-chip, izici ze-ESD ze-chip ngokwayo kufanele zicatshangelwe.Lezi zivame ukushiwo encazelweni ye-chip, futhi ngisho nokusebenza kwe-chip efanayo kubakhiqizi abahlukene kuzohluka.
Naka kakhulu ukuklama futhi ucabangele ngokuningiliziwe, futhi ukusebenza kwebhodi lesifunda kuzoqinisekiswa ngezinga elithile.Kodwa inkinga ye-ESD isengavela, ngakho-ke ukuvikelwa kwenhlangano nakho kubaluleke kakhulu ekuvikelweni kwe-ESD.
66. Lapho wenza ibhodi le-pcb, ukuze kuncishiswe ukuphazamiseka, ingabe ucingo oluphansi kufanele lufake ifomu elivaliwe?
Lapho wenza amabhodi e-PCB, ngokuvamile, kuyadingeka ukunciphisa indawo ye-loop ukuze unciphise ukuphazamiseka.Lapho ubeka ucingo lomhlabathi, akufanele lubekwe ngendlela evaliwe, kodwa ngesimo se-dendritic.Indawo yomhlaba.
67. Uma i-emulator isebenzisa ukunikezwa kwamandla okukodwa futhi ibhodi le-pcb isebenzisa ugesi owodwa, kufanele yini izizathu zamandla kagesi amabili zixhunywe ndawonye?
Kungaba ngcono uma ukunikezwa kwamandla okuhlukile kungasetshenziswa, ngoba akulula ukubangela ukuphazamiseka phakathi kwezinto zamandla, kodwa iningi lemishini inezidingo ezithile.Njengoba i-emulator nebhodi le-PCB zisebenzisa amandla amabili, angicabangi ukuthi kufanele babelane nomhlabathi ofanayo.
68. Isifunda sakhiwe amabhodi amaningana we-pcb.Ingabe kufanele bahlanganyele umhlabathi?
Isekethe iqukethe ama-PCB amaningana, iningi lawo adinga indawo efanayo, ngoba akwenzeki ukusebenzisa amandla amaningana kusekethe eyodwa.Kodwa uma unemibandela ethile, ungasebenzisa ukunikezwa kwamandla okuhlukile, yiqiniso ukuthi ukuphazamiseka kuzoba kuncane.
69. Dala umkhiqizo ophathwa ngesandla nge-LCD negobolondo lensimbi.Uma kuhlolwa i-ESD, ayikwazi ukudlula ukuhlolwa kwe-ICE-1000-4-2, CONTACT ingadlula i-1100V kuphela, futhi i-AIR ingadlula i-6000V.Ekuhlolweni kokuhlanganisa kwe-ESD, okuvundlile kungadlula kuphela ku-3000V, futhi okuqondile kudlule ku-4000V.Imvamisa ye-CPU ingu-33MHZ.Ingabe ikhona indlela yokuphumelela ukuhlolwa kwe-ESD?
Imikhiqizo ephathwa ngesandla iwugqinsi lwensimbi, ngakho-ke izinkinga ze-ESD kufanele zibonakale kakhudlwana, futhi ama-LCD angase abe nezimo ezimbi kakhulu.Uma ingekho indlela yokuguqula izinto zensimbi ezikhona, kunconywa ukuthi wengeze izinto ezilwa nogesi ngaphakathi kwendlela ukuze kuqiniswe inhlabathi ye-PCB, futhi ngesikhathi esifanayo uthole indlela yokumisa i-LCD.Yiqiniso, indlela yokusebenza incike esimweni esithile.
70. Lapho uklama uhlelo oluqukethe i-DSP ne-PLD, yiziphi izici okufanele zicatshangelwe i-ESD?
Ngokuqondene nohlelo olujwayelekile, izingxenye ezithintana ngqo nomzimba womuntu kufanele zicatshangelwe ngokuyinhloko, futhi ukuvikelwa okufanele kufanele kwenziwe kumjikelezo kanye nendlela.Mayelana nokuthi i-ESD izoba nomthelela ongakanani ohlelweni, kuya ngezimo ezahlukahlukene.
Isikhathi sokuthumela: Mar-19-2023