Kusuka emhlabeni we-PCB, Mashi, 19, 2021

Uma senza i-PCB design, sivame ukuhlangana nezinkinga ezihlukahlukene, ezifana nokufanisa i-impedance, imithetho ye-EMI, njll. Lesi sihloko sihlanganise imibuzo ethile nezimpendulo ezihlobene nama-PCB anesivinini esikhulu kuwo wonke umuntu, futhi ngithemba ukuthi kuzoba usizo kuwo wonke umuntu.

1. Ungakucabangela kanjani ukufaniswa kwe-impedance lapho uklama izikimu zedizayini ze-PCB ezinesivinini esikhulu?
Lapho uklama amasekethe e-PCB anesivinini esikhulu, ukufaniswa kwe-impedance kungenye yezinto zokuklama.Inani le-impedance linobudlelwano obuphelele nendlela yezintambo, njengokuhamba phezu kongqimba olungaphezulu (i-microstrip) noma isendlalelo sangaphakathi (i-stripline/double stripline), ibanga ukusuka kungqimba lwereferensi (ungqimba lwamandla noma ungqimba lomhlabathi), ububanzi bezintambo, impahla ye-PCB , njll. Kokubili kuzothinta inani lesici lokuvimbela umkhondo.

Okusho ukuthi, inani le-impedance linganqunywa kuphela ngemuva kwe-wiring.Ngokuvamile, isofthiwe yokulingisa ayikwazi ukucabangela ezinye izimo zezintambo ezingaqhubeki ngenxa yomkhawulo wemodeli yesekethe noma i-algorithm yezibalo esetshenzisiwe.Ngalesi sikhathi, izinqamuli ezithile kuphela (ukunqanyulwa), njengokumelana kochungechunge, ezingagcinwa kumdwebo wohlelo.Nciphisa umthelela wokungaqhubeki ku-trace impedance.Isixazululo sangempela senkinga ukuzama ukugwema ukungaqhubeki kwe-impedance lapho ufaka izintambo.

2. Uma kunamabhulokhi wokusebenza wedijithali/analogi amaningi ebhodini le-PCB, indlela evamile iwukuhlukanisa indawo yedijithali/ye-analogi.Siyini isizathu?
Isizathu sokuhlukanisa umhlabathi wedijithali/i-analogi ingoba isifunda sedijithali sizodala umsindo emandleni nasemhlabeni lapho sishintsha phakathi kwamandla aphezulu naphansi.Ubukhulu bomsindo buhlobene nesivinini sesignali kanye nobukhulu bamanje.

Uma indiza ephansi ingahlukaniswanga futhi umsindo okhiqizwa isekethe yendawo yedijithali mkhulu futhi amasekhethi endawo ye-analog asondelene kakhulu, ngisho noma amasiginali we-digital-to-analog engaweli, isignali ye-analog isazophazanyiswa phansi. umsindo.Okusho ukuthi, indlela engahlukanisiwe ye-digital-to-analog ingasetshenziswa kuphela uma indawo yesifunda se-analog ikude nendawo yesifunda sedijithali edala umsindo omkhulu.

3. Edizayini ye-PCB enesivinini esikhulu, yiziphi izici okufanele umklami acabangele imithetho ye-EMC ne-EMI?
Ngokuvamile, idizayini ye-EMI/EMC idinga ukucabangela kokubili izici ezikhazimulayo neziqhutshwa ngesikhathi esisodwa.Eyangaphambili ingeyengxenye yefrikhwensi ephezulu (>30MHz) kanti eyakamuva iyingxenye yefrikhwensi ephansi (<30MHz).Ngakho awukwazi ukunaka imvamisa ephezulu futhi ungayinaki ingxenye yefrikhwensi ephansi.

Idizayini enhle ye-EMI/EMC kufanele icabangele indawo yedivayisi, ukuhlelwa kwesitaki se-PCB, indlela yokuxhumana ebalulekile, ukukhethwa kwedivayisi, njll. ekuqaleni kwesakhiwo.Uma lingekho ilungiselelo elingcono ngaphambili, lizoxazululwa kamuva.Izothola umphumela ophindwe kabili ngesigamu somzamo futhi yandise izindleko.

Isibonelo, indawo yejeneretha yewashi akufanele ibe seduze nesixhumi sangaphandle ngangokunokwenzeka.Izimpawu zesivinini esikhulu kufanele ziye kungqimba lwangaphakathi ngangokunokwenzeka.Naka ukumadanisa kwesici nokuqhubeka kongqimba lwereferensi ukuze unciphise ukubonakaliswa.Izinga lokubulala lesignali ephushwa idivayisi kufanele libe lincane ngangokunokwenzeka ukuze kuncishiswe ukuphakama.Izingxenye zemvamisa, lapho ukhetha ama-decoupling/bypass capacitor, naka ukuthi impendulo yayo yemvamisa iyahlangabezana yini nezidingo zokunciphisa umsindo endizeni yamandla.

Ukwengeza, naka indlela yokubuya yesiginali yemvamisa ephezulu ukuze wenze indawo yeluphu ibe yincane ngangokunokwenzeka (okungukuthi, i-loop impedance ibe mncane ngangokunokwenzeka) ukunciphisa imisebe.Umhlabathi ungabuye uhlukaniswe ukulawula ububanzi bomsindo we-high-frequency.Ekugcineni, khetha kahle indawo ye-chassis phakathi kwe-PCB nezindlu.

4. Lapho wenza amabhodi e-PCB, ukuze kuncishiswe ukuphazamiseka, ingabe ucingo oluphansi kufanele lufake ifomu lesamba esivaliwe?
Lapho kwenziwa amabhodi e-PCB, indawo eyiluphu ngokuvamile iyancishiswa ukuze kuncishiswe ukuphazamiseka.Lapho ubeka umugqa womhlaba, akufanele ubekwe ngendlela evaliwe, kodwa kungcono ukuyihlela ngendlela yegatsha, futhi indawo yomhlabathi kufanele yande ngangokunokwenzeka.

5. Ungalungisa kanjani i-topology yomzila ukuze uthuthukise ubuqotho besignali?
Lolu hlobo lokuqondisa kwesignali yenethiwekhi luyinkimbinkimbi kakhulu, ngoba kumasignali angaqondile, ama-bidirectional, namasignali amazinga ahlukene, amathonya e-topology ahlukile, futhi kunzima ukusho ukuthi iyiphi i-topology enenzuzo ekuboniseni ikhwalithi.Futhi lapho wenza ukulingisa kwangaphambilini, iyiphi i-topology okufanele isetshenziswe edingeka kakhulu konjiniyela, edinga ukuqonda izimiso zesekhethi, izinhlobo zamasignali, kanye nobunzima bezintambo.

6. Indlela yokubhekana nesakhiwo kanye nezintambo ukuqinisekisa ukuzinza kwamasignali ngaphezu kwe-100M?
Isihluthulelo sezintambo zesignali yedijithali yesivinini esiphezulu ukunciphisa umthelela wezintambo zokudlulisela kukhwalithi yesignali.Ngakho-ke, ukuhlelwa kwamasignali anesivinini esiphezulu ngaphezu kwe-100M kudinga ukulandelwa kwesignali ukuba kube mfushane 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.