Okwamanje, high-frequency kanye ngesivinini PCB idizayini isiphenduke inkambiso, futhi wonke unjiniyela we-PCB Layout kufanele abe nekhono. Okulandelayo, u-Banermei uzokwabelana nawe ngesipiliyoni sokuklama sochwepheshe bezingxenyekazi zekhompuyutha kumasekethe e-PCB avela imvamisa ephezulu kanye nesivinini esikhulu, futhi ngethemba ukuthi kuzoba usizo kuwo wonke umuntu.

1. Ungakugwema kanjani ukuphazamiseka kwefrikhwensi ephezulu?

Umqondo oyisisekelo wokugwema ukuphazamiseka kwe-high-frequency ukunciphisa ukuphazamiseka kwensimu kagesi yamasignali amaza aphezulu, okuyilokho okubizwa nge-crosstalk (Crosstalk). Ungakwazi ukukhulisa ibanga phakathi kwesiginali yesivinini esikhulu kanye nesiginali ye-analogi, noma wengeze imikhondo yokuqapha/shunt eduze kwesiginali ye-analog. Naka futhi ukuphazamiseka komsindo kusuka endaweni yedijithali kuya endaweni ye-analog.

2. 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 yokufaka izintambo, 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 ezinokuvinjelwa okungaqhubeki ngenxa yomkhawulo wemodeli yesifunda 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.

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. Umklamo omuhle we-EMI/EMC kufanele ucabangele indawo yedivayisi, ukuhlelwa kwesitaki se-PCB, indlela yokuxhumana ebalulekile, ukukhethwa kwedivayisi, njll. ekuqaleni kwesakhiwo. Uma lingekho ilungiselelo elingcono ngaphambili, lizoxazululwa kamuva. Izokwenza kabili umphumela ngesigamu somzamo futhi ikhulise izindleko. Isibonelo, indawo yejeneretha yewashi akufanele ibe seduze nesixhumi sangaphandle. 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 i-decoupling/bypass capacitor, naka ukuthi impendulo yayo yemvamisa iyahlangabezana yini nezidingo zokunciphisa umsindo endizeni yamandla. Ngaphezu kwalokho, naka indlela yokubuya yesiginali yemvamisa ephezulu ukuze wenze indawo yeluphu ibe mncane 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. Ungakhetha kanjani ibhodi le-PCB?

Ukukhethwa kwebhodi le-PCB kufanele kube nebhalansi phakathi kwezidingo zedizayini yokuhlangabezana nokukhiqizwa ngobuningi nezindleko. Izidingo zokuklama zihlanganisa kokubili izingxenye zikagesi nezemishini. Ngokuvamile le nkinga yezinto ezibonakalayo ibaluleke kakhulu lapho uklama amabhodi e-PCB anesivinini esikhulu (imvamisa enkulu kune-GHz). Isibonelo, izinto ezisetshenziswa kakhulu ze-FR-4, ukulahleka kwe-dielectric ngemvamisa yama-GHz amaningana kuzoba nomthelela omkhulu ekuncipheni kwesignali, futhi kungase kungafaneleki. Mayelana nogesi, qaphela ukuthi ukulahleka kwe-dielectric kanye ne-dielectric kufanelekile yini imvamisa eklanyelwe.

5. Ungahlangabezana kanjani nezidingo ze-EMC ngangokunokwenzeka ngaphandle kokubanga ingcindezi yezindleko ezinkulu?

Izindleko ezikhuphukile zebhodi le-PCB ngenxa ye-EMC ngokuvamile kungenxa yokwanda kwenani lezendlalelo zomhlabathi zokuthuthukisa umphumela wokuvikela kanye nokwengezwa kobuhlalu be-ferrite, ukuklinywa namanye amadivaysi okucindezela ama-harmonic we-high-frequency. Ngaphezu kwalokho, ngokuvamile kuyadingeka ukufanisa isakhiwo sokuvikela kwezinye izikhungo ukwenza lonke uhlelo luphumelele izidingo ze-EMC. Okulandelayo kunikeza kuphela izindlela ezimbalwa zokuklama ibhodi le-PCB ukuze kuncishiswe umphumela wemisebe kagesi okhiqizwa isekethe.

Zama ukukhetha idivayisi enezinga eliphansi lokubulala lesignali ukuze unciphise izingxenye zefrikhwensi ephezulu ekhiqizwa isignali.

Naka ukubekwa kwezingxenye zemvamisa ephezulu, hhayi eduze kakhulu nesixhumi sangaphandle.

Naka ukufaniswa kwe-impedance kwamasignali esivinini esikhulu, isendlalelo sezintambo kanye nendlela yamanje yokubuya, ukunciphisa ukubonakaliswa kwe-high-frequency kanye nemisebe.

Beka ama-decoupling capacitor anele futhi afanele kumaphini wokuphakela amandla wedivayisi ngayinye ukuze unciphise umsindo endizeni yamandla nendiza yaphansi. Naka ngokukhethekile ukuthi impendulo yemvamisa nezici zokushisa ze-capacitor ziyahlangabezana yini nezidingo zokuklama.

Umhlabathi oseduze nesixhumi sangaphandle ungahlukaniswa kahle nomhlabathi, futhi inhlabathi yesixhumi ingaxhunywa endaweni ye-chassis eseduze.

Ukugada okuphansi/ukulandela umkhondo kungasetshenziswa ngokufanelekile eceleni kwezimpawu ezikhethekile zesivinini esikhulu. Kodwa naka umthelela wokulandela umkhondo we- guard/shunt on the impedance character of the trace.

Isendlalelo samandla sishwabana ngo-20H kusukela kungqimba lomhlabathi, futhi H ibanga phakathi kongqimba lwamandla kanye nongqimba lomhlabathi.

6. Yiziphi izici okufanele zinakwe lapho uklama, umzila kanye nesakhiwo se-PCB evama kakhulu ngaphezu kwe-2G?

Ama-PCB anemvamisa ephezulu ngaphezu kwe-2G ayingxenye yedizayini yamasekhethi omsakazo futhi awekho ngaphakathi kobubanzi bengxoxo yomklamo wesekethe yedijithali enesivinini esikhulu. Isakhiwo kanye nomzila wesekethe yefrikhwensi yomsakazo kufanele kucatshangelwe kanye nohlelo, ngoba ukwakheka kanye nomzila kuzodala imiphumela yokusabalalisa. Ngaphezu kwalokho, ezinye izinto ezisetshenziswayo ekwakhiweni kwamasekhethi omsakazo wenziwa ngokusebenzisa izincazelo ezinepharamitha kanye namafoil ethusi anomumo okhethekile. Ngakho-ke, amathuluzi e-EDA ayadingeka ukuhlinzeka ngamadivayisi anepharamitha futhi ahlele amafoyili ethusi anomumo okhethekile. Isiteshi se-Mentor’s boardstation sinemojula ekhethekile ye-RF design engahlangabezana nalezi zidingo. Ngaphezu kwalokho, ukwakheka okujwayelekile kwe-RF kudinga amathuluzi akhethekile okuhlaziya isekethe ye-RF. Okudume kakhulu embonini i-agilent’s eesoft, enokuxhumana okuhle namathuluzi e-Mentor.

7. Ingabe ukwengeza amaphuzu okuhlola kuzothinta ikhwalithi yamasignali anesivinini esikhulu?

Ukuthi izothinta ikhwalithi yesignali kuncike endleleni yokwengeza amaphuzu okuhlola nokuthi isignali ishesha kangakanani. Ngokuyisisekelo, amaphuzu okuhlola engeziwe (ungasebenzisi iphinikhodi ekhona nge-DIP noma njengamaphoyinti okuhlola) angase engezwe emugqeni noma adonse umugqa omfushane emgqeni. Owokuqala ulingana nokwengeza i-capacitor encane emgqeni, lo wokugcina igatsha elengeziwe. Zombili lezi zimo zizothinta isignali yesivinini esikhulu kakhulu noma ngaphansi, futhi izinga lomphumela lihlobene nesivinini semvamisa yesignali kanye nesilinganiso somkhawulo wesignali. Ubukhulu bomthelela bungaziwa ngokulingisa. Empeleni, iphoyinti lokuhlola lincane, lingcono (Yebo, kufanele lihlangabezane nezidingo zethuluzi lokuhlola) lifushane igatsha, lingcono.