Okwangoku, i-high-frequency kunye Isantya esiphezulu sePCB uyilo lube yeyona nto iphambili, kwaye yonke injineli yoYilo lwePCB kufuneka ibe nobuchule. Okulandelayo, i-Banermei iya kukwabelana nawe ngamava oyilo lweengcali ze-hardware kwi-high-frequency kunye ne-high-speed PCB circuits, kwaye ndiyathemba ukuba iya kuba luncedo kumntu wonke.

1. Ukuphepha njani ukuphazamiseka okuphezulu?

Umbono osisiseko wokunqanda uphazamiseko oluphezulu kukunciphisa uphazamiseko lwe-electromagnetic field of high-frequency signals, ebizwa ngokuba yi-crosstalk (Crosstalk). Unokwandisa umgama phakathi kwesignali yesantya esiphezulu kunye nesignali ye-analog, okanye ungeze umlindi womhlaba / umkhondo we-shunt ecaleni kwesignali ye-analog. Kwakhona qaphela ukuphazamiseka kwengxolo ukusuka kumhlaba wedijithali ukuya kumhlaba we-analog.

2. Ukuqwalasela njani ukuthelekiseka kokumelana xa uyila i-schematics yoyilo lwePCB enesantya esiphezulu?

Xa uyila iisekethe zePCB ezinesantya esiphezulu, ukuthelekisa i-impedance yenye yezinto zoyilo. Ixabiso le-impedance linobudlelwane obupheleleyo kunye nendlela yocingo, njengokuhamba kwi-surface layer (microstrip) okanye i-inner layer (i-stripline / i-stripline ephindwe kabini), umgama ukusuka kuluhlu lwereferensi (umaleko wamandla okanye umaleko womhlaba), ububanzi be-wiring, izinto zePCB. , njl. Zombini ziya kuchaphazela ixabiso leempawu zokuthintela umkhondo. Oko kukuthi, ixabiso le-impedance linokumiselwa kuphela emva kwe-wiring. Ngokuqhelekileyo, isofthiwe yokulinganisa ayikwazi ukuqwalasela ezinye iimeko ze-wiring kunye ne-impedance engapheliyo ngenxa yokunciphisa imodeli yesiphaluka okanye i-algorithm yemathematika esetyenzisiweyo. Ngeli xesha, kuphela ezinye i-terminators (ukupheliswa), ezifana nokuchasana kochungechunge, zinokugcinwa kwi-diagram yesikimu. Nciphisa isiphumo sokungaqhubeki kwi-trace impedance. Isisombululo sokwenyani kwingxaki kukuzama ukunqanda i-impedance discontinuities xa i-wiring.

3. Kuyilo lwePCB olunesantya esiphezulu, yeyiphi imiba ekufuneka umyili ayiqwalasele imithetho ye-EMC kunye ne-EMI?

Ngokubanzi, uyilo lwe-EMI/EMC kufuneka luthathele ingqalelo yomibini imiba enemitha kunye neqhutywa ngaxeshanye. Eyangaphambili yeyaphezulu inxalenye yefrikhwensi (<30MHz) kwaye le yokugqibela yinxalenye yefrikhwensi esezantsi (<30MHz). Ke awungekhe uhoye i-frequency ephezulu kwaye ungayihoyi indawo ephantsi. Uyilo olulungileyo lwe-EMI/EMC kufuneka luthathele ingqalelo indawo yesixhobo, ilungiselelo lokupakishwa kwePCB, indlela yoqhagamshelo ebalulekileyo, ukhetho lwesixhobo, njl. njl. ekuqaleni koyilo. Ukuba akukho malungiselelo angcono ngaphambili, aya kusonjululwa emva koko. Kuya kwenza kabini umphumo ngesiqingatha somzamo kunye nokwandisa iindleko. Ngokomzekelo, indawo yejeneretha yewotshi akufanele isondele kumdibanisi wangaphandle. Izibonakaliso zesantya esiphezulu kufuneka ziye kumaleko angaphakathi kangangoko kunokwenzeka. Nikelani ingqalelo kuphawu lwe-impedance ehambelanayo kunye nokuqhubeka komgangatho wereferensi ukunciphisa ukubonakaliswa. Izinga lokubulala lomqondiso elityhalwe sisixhobo kufuneka libe lincinci kangangoko ukunciphisa ukuphakama. Amacandelo e-frequency, xa ukhetha i-decoupling / bypass capacitor, qwa lasela ukuba impendulo yayo ye-frequency ihlangabezana neemfuno zokunciphisa ingxolo kwindiza yamandla. Ukongezelela, nikela ingqalelo kwindlela yokubuya ye-high-frequency signal current ukuze wenze indawo ye-loop ibe yincinci kangangoko (oko kukuthi, i-loop impedance incinci kangangoko kunokwenzeka) ukunciphisa imitha. Umhlaba ungahlulwa kwakhona ukulawula uluhlu lwengxolo ephezulu-frequency. Okokugqibela, khetha ngokufanelekileyo umhlaba we-chassis phakathi kwePCB kunye nendlu.

4. Indlela yokukhetha ibhodi yePCB?

Ukhetho lwebhodi yePCB kufuneka lubethe ulungelelwano phakathi kweemfuno zoyilo loyilo kunye nemveliso yobuninzi kunye neendleko. Iimfuno zoyilo ziquka zombini iindawo zombane kunye nezomatshini. Ngokuqhelekileyo le ngxaki imathiriyeli ibaluleke kakhulu xa uyila iibhodi zePCB ezinesantya esiphezulu (i-frequency enkulu kuneGHz). Ngokomzekelo, izinto ezisetyenziswa ngokuqhelekileyo ze-FR-4, ilahleko ye-dielectric kwi-frequency ye-GHz eziliqela iya kuba nempembelelo enkulu ekunciphiseni umqondiso, kwaye isenokungafaneleki. Ngokubhekiselele kumbane, qaphela ukuba ingaba i-dielectric constant kunye nelahleko ye-dielectric ifanelekile kwi-frequency eyilelwe.

5. Uhlangabezana njani neemfuno ze-EMC kangangoko ngaphandle kokubangela uxinzelelo lweendleko ezininzi?

Iindleko ezongeziweyo zebhodi ye-PCB ngenxa ye-EMC idla ngenxa yokwanda kwenani leengqimba zomhlaba zokuphucula umphumo wokukhusela kunye nokongezwa kwe-ferrite bead, ukuminxa kunye nezinye izixhobo zokucinezela i-harmonic high-frequency. Ukongezelela, ngokuqhelekileyo kuyimfuneko ukufanisa isakhiwo sokukhusela kwamanye amaziko ukwenza inkqubo yonke iphumelele iimfuno ze-EMC. Oku kulandelayo kuphela kubonelela ngeendlela ezimbalwa zoyilo lwebhodi yePCB ukunciphisa isiphumo sombane wombane oveliswa yisekethe.

Zama ukukhetha isixhobo esinesantya esicothayo sokubulala umqondiso ukunciphisa iinxalenye eziphezulu zefrikhwensi eyenziwe ngumqondiso.

Nika ingqalelo ekubekweni kwamacandelo aphezulu-frequency, engasondeli kakhulu kwisixhumi sangaphandle.

Nikelani ingqalelo kwi-impedance ehambelana neempawu zesantya esiphezulu, i-wiring layer kunye nendlela yokubuya kwayo ngoku, ukunciphisa ukubonakaliswa kwe-high-frequency reflection kunye ne-radiation.

Beka i-decoupling capacitors eyaneleyo kwaye ifanelekileyo kwizikhonkwane zonikezelo lwamandla kwisixhobo ngasinye ukunciphisa ingxolo kwinqwelomoya yamandla kunye nenqwelomoya ephantsi. Nika ingqalelo ekhethekileyo ukuba ngaba ukuphendulwa rhoqo kunye neempawu zokushisa ze-capacitor zihlangabezana neemfuno zoyilo.

Umhlaba okufutshane nomdibaniso wangaphandle unokwahlulwa ngokufanelekileyo kumhlaba, kwaye umhlaba wekhonkco unokudibaniswa kumhlaba we-chassis okufutshane.

Umlindi ophantsi/umkhondo we-shunt unokusetyenziswa ngokufanelekileyo ecaleni kwemiqondiso ekhethekileyo enesantya esiphezulu. Kodwa nikela ingqalelo kwimpembelelo yomlindi / umkhondo we-shunt kuphawu lokuthintela umkhondo.

Uluhlu lwamandla lunciphisa i-20H ukusuka kuluhlu lomhlaba, kwaye i-H ngumgama phakathi komgangatho wamandla kunye nomgangatho womhlaba.

6. Yeyiphi imiba ekufuneka inikwe ingqwalasela xa uyila, uhambisa indlela kunye noyilo lwe-PCB yamaxesha amaninzi ngaphezulu kwe-2G?

Ii-PCB ezikwi-frequency ephezulu ngaphezulu kwe-2G zezoyilo lweesekethe zamaza kanomathotholo kwaye azikho ngaphakathi kwendawo yengxoxo yoyilo lwesekethe yedijithali enesantya esiphezulu. Uyilo kunye nendlela yesekethe yamaza kanomathotholo kufuneka ithathelwe ingqalelo kunye neskim, kuba uyilo kunye nendlela iya kubangela iziphumo zokusasazwa. Ngaphaya koko, ezinye izixhobo zokwenziwa kuyilo lweesekethe zerediyo zerediyo zibonwa ngokuchazwa kweeparamitha kunye neefoyile zobhedu ezinokwakheka okukhethekileyo. Ngoko ke, izixhobo ze-EDA zifunekayo ukubonelela ngezixhobo zeparameterized kwaye uhlele iifoyile zobhedu ezinokwakheka okukhethekileyo. Isikhululo sebhodi yeMentor sinemodyuli yoyilo ekhethekileyo yeRF enokuthi ihlangabezane nezi mfuno. Ngaphezu koko, uyilo lweRF ngokubanzi lufuna izixhobo ezikhethekileyo zohlalutyo lwesekethe yeRF. Eyona idumileyo kwishishini yi-eesoft ye-agilent, enojongano oluhle kunye nezixhobo zeMentor.

7. Ngaba ukongezwa kwamanqaku okuvavanya kuya kuchaphazela umgangatho weempawu zesantya esiphezulu?

Ingaba iya kuchaphazela umgangatho wesignali ixhomekeke kwindlela yokongeza amanqaku okuvavanya kunye nokukhawuleza kwesibonakaliso. Ngokwenene, amanqaku ovavanyo olongezelelweyo (ungasebenzisi i-pin ekhoyo okanye i-DIP njengamanqaku okuvavanya) anokongezwa kumgca okanye utsalwe umgca omfutshane ukusuka kumgca. Eyangaphambili ilingana nokongeza i-capacitor encinci kumgca, lo mva isebe elongezelelweyo. Zomibini le miqathango iya kuchaphazela umqondiso wesantya esiphezulu ngaphezulu okanye ngaphantsi, kwaye ubungakanani besiphumo buhambelana nesantya sesantya somqondiso kunye nesantya somda wesignali. Ubungakanani bempembelelo bukwaziwa ngokulinganisa. Ngokomgaqo, incinci inqaku lokuvavanya, ngcono (ngokuqinisekileyo, kufuneka ihlangabezane neemfuno zesixhobo sokuvavanya) imfutshane isebe, ingcono.