Ukusuka kwihlabathi lePCB
1. 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 emva kwe-wiring.Ngokuqhelekileyo, i-software yokulinganisa ayinakuthathela ingqalelo ezinye iimeko zokunqanda i-wiring 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 ukungaqhubeki kwe-impedance xa i-wiring.
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2. Xa kukho iibhloko ezininzi zedijithali / ze-analog kwibhodi ye-PCB, indlela eqhelekileyo kukwahlula umhlaba wedijithali / we-analog.Siyintoni isizathu?
Isizathu sokwahlula umhlaba wedijithali / we-analog kukuba isekethe yedijithali iya kuvelisa ingxolo kumandla kunye nomhlaba xa utshintshela phakathi kwezinto eziphezulu kunye neziphantsi.Ubungakanani bengxolo bunxulumene nesantya somqondiso kunye nobukhulu bangoku.
Ukuba inqwelomoya yomhlaba ayahlulwanga kwaye ingxolo eyenziwa yi-digital area circuit inkulu kwaye iisekethe zendawo ye-analog zisondele kakhulu, nokuba i-digital-to-analog signals ayidluli, isignali ye-analog isaza kuphazanyiswa ngumhlaba. ingxolo.Oko kukuthi, indlela engahlulwanga yedijithali-kwi-analog ingasetyenziswa kuphela xa indawo yesekethe ye-analog ikude nommandla wesekethe yedijithali eyenza ingxolo enkulu.
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 yeyecandelo eliphezulu lefrikhwensi (> 30MHz) kwaye le yokugqibela yinxalenye yefrikhwensi esezantsi (<30MHz).Ke awungekhe uhoye nje i-frequency ephezulu kwaye ungayihoyi i-frequency ephantsi.
Uyilo oluhle lwe-EMI/EMC kufuneka luthathele ingqalelo indawo yesixhobo, ilungiselelo le-stack ye-PCB, indlela yoqhagamshelo ebalulekileyo, ukhetho lwesixhobo, njl. ekuqaleni koyilo.Ukuba akukho malungiselelo angcono ngaphambili, aya kusonjululwa emva koko.Iya kufumana umphumo ophindwe kabini ngesiqingatha somzamo kunye nokwandisa iindleko.
Ngokomzekelo, indawo yejeneretha yewotshi akufanele ibe kufuphi nekhonkco yangaphandle ngokusemandleni.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 capacitors, qaphela ukuba impendulo yayo ye-frequency ihlangabezana neemfuno zokunciphisa ingxolo kwi-plane 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.
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4. Xa usenza ibhodi ye-pcb, ukwenzela ukunciphisa ukuphazamiseka, ngaba ucingo lomhlaba kufuneka lufake ifom evaliweyo?
Xa usenza iibhodi PCB, indawo loop iyancipha ngokubanzi ukwenzela ukunciphisa ukuphazamiseka.Xa ubeka umgca womhlaba, akufanele ubekwe kwifom evaliweyo, kodwa kungcono ukuyilungisa ngendlela yesebe, kwaye indawo yomhlaba kufuneka inyuswe ngokusemandleni.
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5. Indlela yokulungelelanisa i-topology yomzila ukuphucula imfezeko yomqondiso?
Olu hlobo lwesalathiso somqondiso womnatha lunzima ngakumbi, kuba kwi-unidirectional, izibonakaliso ze-bidirectional, kunye neentlobo ezahlukeneyo zemigangatho yeempawu, iimpembelelo ze-topology zihlukile, kwaye kunzima ukusho ukuba yeyiphi i-topology enenzuzo kumgangatho wesignali.Kwaye xa usenza ukulinganisa kwangaphambili, yeyiphi i-topology yokusebenzisa ifuna kakhulu kwiinjineli, ifuna ukuqonda imigaqo yesekethe, iintlobo zesignali, kunye nobunzima bocingo.
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6. Indlela yokujongana ne-layout kunye ne-wiring ukuqinisekisa ukuzinza kweempawu ngaphezu kwe-100M?
Isitshixo kwi-high-speed digital signal wiring kukunciphisa impembelelo yemigca yokuhambisa kumgangatho wesignali.Ngoko ke, ukucwangciswa kweempawu zesantya esiphezulu ngaphezu kwe-100M kufuna ukuba iimpawu zesignali zibe mfutshane njengoko kunokwenzeka.Kwiisekethe zedijithali, izibonakaliso zesantya esiphezulu zichazwe ngexesha lokulibaziseka kokunyuka kwesignali.
Ngaphezu koko, iintlobo ezahlukeneyo zemiqondiso (ezifana ne-TTL, GTL, LVTTL) zineendlela ezahlukeneyo zokuqinisekisa umgangatho womqondiso.