Ubeko yenye yezona zakhono zisisiseko zomsebenzi Uyilo PCB injineli. Umgangatho we-wiring uya kuchaphazela ngokuthe ngqo ukusebenza kwayo yonke le nkqubo, uninzi lweyona ithiyori yesantya esiphezulu kufuneka igqitywe kwaye iqinisekiswe luLwakhiwo, ukuze kubonwe ukuba i-wiring ibalulekile kuyilo olukhawulezayo lwe-PCB. Oku kulandelayo kuya kuba kukujonga kwe-wiring yokwenyani inokuhlangabezana neemeko ezithile, uhlalutyo lobungqingqwa bayo, kunye nokubonelela ngesicwangciso esiliqili sokuhamba. Ngokukodwa ukusuka kumgca we-Angle yasekunene, ulwahlulo lomgca, umgca wenyoka kwaye njalo kwimiba emithathu yokucacisa.

1. I-Rectangular go line

Ukufakelwa kwe-engile engasekunene ngokubanzi kuyafuneka ukuthintela imeko kwi-wiring ye-PCB, kwaye sele iphantse yaba yenye yemigangatho yokulinganisa umgangatho we-wiring, ngoko ke zingakanani iimpembelelo eziya kubakho kwi-angle-angle wiring ekuhanjisweni komqondiso? Ngokomgaqo, ii-wiring zekona lasekunene ziya kutshintsha ububanzi bomgca womgca wokuhambisa, kukhokelela ekuphelisweni kwe-impedance. Ngapha koko, ayisiyiyo kuphela ilayini ye-Angle elungileyo, i-Angle yethoni, umgca we-Angle oyingozi unokubangela utshintsho kwi-impedance.

Impembelelo yokulungelelaniswa kwekona lasekunene kwisiginali ibonakala ikakhulu kwizinto ezintathu: okokuqala, ikona inokulingana nomthwalo we-capacitive kulayini wokuhambisa, ukunciphisa ixesha lokunyuka; Okwesibini, ukupheliswa kwe-impedance kuya kubangela ukubonakaliswa komqondiso; Okwesithathu, i-EMI iveliswe ngencam eyi-Angle tip.

Amandla e-parasitic capacitance abangelwa li-Angle elungileyo yomgca wokudlulisela angabalwa ngale ndlela ifanelekileyo:

C = 61W (Er) 1/2 / Z0

Kule fomyula ingentla, u-C ubhekisa kumandla alinganayo ekoneni (pF), W ubhekisa kububanzi bomgca (intshi), ε R ubhekisa kwi-dielectric rhoqo ye-medium, kunye ne-Z0 luphawu lokuhambisa umgca. Umzekelo, kwi-4Mils 50 ohm yokudlulisela umgca (εr 4.3), amandla e-Angle elungileyo imalunga ne-0.0101pF, kwaye umahluko wokunyuka kwexesha unokuqikelelwa:

T10-90% = 2.2 * C * z0 / 2 = 2.2 * 0.0101 * 50/2 = 0.556ps

Kuyabonakala ukusuka kubalo ukuba amandla e-capacitance aziswe yi-angle-angle wiring amancinci kakhulu.

Njengoko ububanzi bomgca we-angle-angle line benyuka, i-impedance kweli nqanaba iya kuncipha, ngoko kuya kubakho umqondiso othile wokubonakalisa uphawu. Sinokubala i-impedance elinganayo emva kokuba ububanzi bomgca bonyukile ngokungqinelana nefomula yokubala ye-impedance ekhankanywe kwicandelo lemigca yokuhambisa, emva koko sibala ukungalingani kokubonisa ngokomgaqo wobungqina: ρ = (Zs-Z0) / (Zs + Z0), i-wiring ye-angle engasekunene ngokubanzi ekhokelela kutshintsho lwe-impedance phakathi kwe-7% -20%, ke owona mlinganiso uphezulu wokubonisa umalunga ne-0.1. Ngapha koko, njengoko kunokubonwa kumfanekiso ongezantsi, umgca wokuhambisa we-impedance utshintsha ubuncinci kubude be-W / 2, kwaye emva koko ubuyisele kwisithintelo esiqhelekileyo emva kwexesha le-W / 2. Ixesha lotshintsho olupheleleyo lwe-impedance lifutshane kakhulu, ngesiqhelo kwi-10ps. Utshintsho olukhawulezileyo nolunje phantse alunakubakho kuhambiso lomqondiso ngokubanzi.

Abantu abaninzi banokuqonda okunje ngokuhamba nge-engile elungileyo, bekholelwa ukuba incam kulula ukuyikhupha okanye ukufumana amaza ombane kwaye ivelise i-EMI, eye yaba sesinye sezizathu zokuba kutheni abantu abaninzi becinga ukuba indlela ejikelezayo ayinakwenzeka. Nangona kunjalo, uninzi lweziphumo zovavanyo olusebenzayo zibonisa ukuba umgca we-engile elungileyo awuvelisi i-EMI eninzi kunelayini ethe nkqo. Mhlawumbi ukusebenza kwesixhobo sangoku kunye nenqanaba lovavanyo kuthintela ukuchaneka kovavanyo, kodwa ubuncinci kubonisa ukuba imitha yelayini engasekunene ingaphantsi kwempazamo yomlinganiselo wesixhobo ngokwaso. Ngokubanzi, ulungelelwaniso lwe-engile engasekunene ayoyikisi njengoko inokubonakala ngathi. Ubuncinci kwizicelo ezingezantsi kwe-GHz, naziphi na iziphumo ezinje nge-capacitance, ukubonakalisa, i-EMI, njl. Injineli yoyilo ye-PCB ekhawulezayo kufuneka ijolise kulwakhiwo, amandla / uyilo lomhlaba, uyilo lweentambo, ukugqobhoza, njl. Nangona, ewe, iimpembelelo zemigca yoxande ayixakekanga kakhulu, kodwa ayitsho ukuba singahamba ngecala le-Angle elungileyo, ingqalelo kwiinkcukacha ngumgangatho obalulekileyo wazo zonke iinjineli ezilungileyo, kwaye, ngokukhula ngokukhawuleza kweesekethe zedijithali , Iinjineli zePCB ukuqhubekeka kwamaza ombane nako kuya kuqhubeka ukuphucula, ukuya kuthi ga ngaphezulu kwe-10 GHZ RF intsimi yoyilo, Ezi engile zincinci zincinci zinokugxila kwiingxaki zesantya esiphezulu.

2. Umahluko we

Isibonakaliso seDigerenTIal sisetyenziswa ngokubanzi kuyilo lweesekethe ezinesantya esiphezulu. Olona Phawu lubaluleke kakhulu kwisekethe luLwakhiwo lweMpawu zoLuhlu lweDigitalTIal. Uqinisekisa njani ukusebenza kwayo kakuhle kuyilo lwePCB? Ngale mibuzo mibini engqondweni, siya kwinqanaba elilandelayo lengxoxo.

Uthini umahluko? NgesiNgesi esicacileyo, umqhubi uthumela imiqondiso emibini elinganayo kunye neguqulweyo, kwaye umamkeli uthelekisa umahluko phakathi kwemithambo emibini ukumisela ukuba imeko eyiyo ngu “0” okanye “1”. Isibini seengcingo eziphethe imiqondiso eyahlukileyo ibizwa ngokuba ziingcingo ezahlukeneyo.

Xa kuthelekiswa nokuhamba rhoqo kwesiginali esisigxina, umqondiso owahlukileyo unezona zinto zibalulekileyo kwezi zinto zintathu zilandelayo:

Isakhono sokulwa nokuphazamiseka esomeleleyo, kuba ukudibana phakathi kwemigca emibini eyahlukileyo kulungile kakhulu, xa kukho ukuphazamiseka kwengxolo, ziphantse zadityaniswa kwimigca emibini ngaxeshanye, kwaye umamkeli ukhathalela kuphela umahluko phakathi kwale miqondiso mibini, ke ingxolo yohlobo oluqhelekileyo lwangaphandle inokucinywa ngokupheleleyo.

Inokucinezela ngokufanelekileyo i-EMI. Kwangokunjalo, ngenxa yokuba imiqondiso emibini iphambene, intsimi ye-electromagnetic ekhutshwe ngabo inokurhoxisa. Ukusondela kokudibanisa kukuncipha kwamandla ombane okhutshelwa kwilizwe langaphandle.

C. Ukubeka ixesha kuchanekile. Kuba utshintsho lotshintsho lweempawu ezahlukileyo lubekwe kwindawo ekudibana kuyo imiqondiso emibini, ngokungafaniyo neempawu eziye ziphele ezigwetywa yimilinganiselo ephezulu kunye nephantsi, ayichaphazeleka kakhulu kwinkqubo kunye neqondo lobushushu, elinokunciphisa iimpazamo zexesha kwaye lifaneleke ngakumbi iisekethe ezinempawu ezibonisa ukuphakama okuncinci. I-LVDS (amandla ombane aphantsi okwahlukileyo IUkusayina) kubhekisa kule teknoloji yesignali yesahluko esincinci.

Kwiinjineli zePCB, eyona nkxalabo ibaluleke kakhulu yindlela yokuqinisekisa ukuba ezi zibonelelo zendlela eyahlukileyo zinokusetyenziswa ngokupheleleyo kulungelelwaniso lwangempela. Mhlawumbi nje xa unxibelelana noLwakhiwo abantu baya kuziqonda iimfuno ngokubanzi zendlela eyahlukileyo, oko kukuthi “ubude obulinganayo, umgama olinganayo”. I-Isometric kukuqinisekisa ukuba imiqondiso emibini eyahlukileyo ihlala igcina ukungafani, ukunciphisa icandelo lendlela eqhelekileyo; I-Isometric ikakhulu iqinisekisa ukungafani okufanayo, ukunciphisa ukubonakaliswa. “Ngokusondela ngokukhawuleza” ngamanye amaxesha enye yeemfuno zendlela eyahlukileyo. Kodwa akukho namnye kule mithetho wenzelwe ukuba usetyenziswe ngoomatshini, kwaye uninzi lweenjineli kubonakala ngathi abaluqondi uhlobo lokwahlula ngesantya esiphezulu. Oku kulandelayo kugxile kwiimpazamo ezininzi eziqhelekileyo kuyilo lwesahluko se-PCB.

I-1 engeyonyani: Imiqondiso eyahlukileyo ayifuni moya yaphantsi njengendlela yokubuyela umva, okanye ucinga ukuba imigca yokwahlula inikezela ukubuyela umva komnye komnye. Unobangela wokungaqondani kakuhle udidekile yinto yomphezulu, okanye indlela yokuhambisa isantya esiphezulu ayonelanga ngokwaneleyo. Njengoko kunokubonwa kulwakhiwo lwesiphelo sokufumana kwi-FIG. 1-8-15, ii-emitter currents ze-transistors Q3 kunye ne-Q4 ziyalingana kwaye zichasene, kwaye okwangoku kwindawo yokudibana ngokurhoxiswa ngokuchanekileyo (I1 = 0). Ke ngoko, umahluko wesekethe awukhathalele iiprojekti ezifanayo zomhlaba kunye neminye imiqondiso yengxolo enokubakho kunikezelo lwamandla nakwindiza yasemhlabeni. Ukucinywa kwenxalenye yokubuyela umva kwenqwelomoya emhlabeni oko akuthethi ukuba isekethe yokwahlula ayithathi inqwelomoya njengendawo yokubuyela umqondiso. Ngapha koko, kuhlalutyo lokubuyela umva komqondiso, indlela yokwahlula eyahlukileyo iyafana naleyo yomgaqo oqhelekileyo wokugqibela, oko kukuthi, phezulu

Umqondiso wokuhamba rhoqo uhlala ubuya umva kwisekethe kunye nokuncipha okuncinci. Umahluko omkhulu kulele kumgca wokwahlulahlula kungekuphela kokudibana emhlabeni, kodwa kunye nokudibanisa phakathi komnye nomnye. Ukudibana okuqinileyo kuba yindlela ephambili yokuhamba kwakhona.

Kuyilo lwesekethe ye-PCB, ukudibanisa phakathi kwe-wiring umahluko ngokubanzi kuncinci, kuhlala kubalwa i-10 ~ 20% kuphela yesidanga sokudibanisa, kwaye uninzi lokudibanisa lusemhlabeni, ke eyona ndlela iphambili yokubuyela umva ye-wiring eyahlukileyo isekhona emhlabeni inqwelomoya. Kwimeko yokupheliswa kwenqwelomoya yendawo, ukudibana phakathi kweendlela ezahlukileyo kubonelela ngendlela ephambili yokubuyela umva kommandla ngaphandle kwenqwelomoya, njengoko kubonisiwe kwi-FIG. 1-8-17. Nangona ifuthe lokuyekiswa kwendiza ekubhekiswa kuyo kwi-wiring eyahlukileyo ayisiyonto imbi njengaleyo ye-wiring enye yesiqhelo, isaza kunciphisa umgangatho wophawu lokwahlula kunye nokunyusa i-EMI, ekufuneka ithintelwe kangangoko kunokwenzeka. Abanye abayili bakholelwa ukuba isalathiso senqwelomoya somgca wosasazo lokwahlulahlula lungasuswa ukucinezela inxenye yesiginali yemodi eqhelekileyo kusasazo olwahlukileyo, kodwa ithiyori le ndlela ayinqweneleki. Ulawula njani i-impedance? Ngaphandle kokubonelela nge-impedance loop yomhlaba yempawu eqhelekileyo, imitha ye-EMI iya kubangelwa, eyenzakalisa ngakumbi kunokuba ilungile.

Intsomi 2: Ukugcina isithuba esilinganayo kubaluleke ngakumbi kunokulinganisa ubude bomgca. Kwi-wiring ye-PCB eyiyo, ihlala ingakwazi ukuhlangabezana neemfuno zoyilo olwahlukileyo. Ngenxa yokuhanjiswa kwezikhonkwane, imingxunya, kunye nendawo yokufaka iingcingo kunye nezinye izinto, kuyimfuneko ukufezekisa injongo yokulinganisa ubude bomgca ngokujija okufanelekileyo, kodwa isiphumo ngokuqinisekileyo siyinxalenye yokwahluka kwesibini akunakulinganiswa, ngeli xesha, njani ukukhetha? Ngaphambi kokuba sitsibe kwisiphelo, makhe sijonge ezi ziphumo zilandelayo zokulinganisa. Ingabonakala kwezi ziphumo zingentla zokulinganisa ukuba ifomathi yesikimu 1 kunye ne-Scheme 2 ziphantse zangqamana, oko kukuthi, ifuthe lokungalingani kwezithuba lincinci, kwaye iimpembelelo zobude bomgca wokungalingani zinkulu kakhulu kulandelelwano lwamaxesha (Isikimu 3) . Ukusuka kwimbono yohlalutyo lwethiyori, nangona ukungangqinelani kwesithuba kuya kukhokelela kutshintsho lwempedance, kodwa ngenxa yokuba ukudibanisa phakathi kwezahluko ngokwawo akubalulekanga, ke uluhlu lweenguqu ze-impedance lincinci kakhulu, zihlala phakathi kwe-10%, kuphela ngokulinganayo Ukubonakalisa okubangelwa ngumngxuma, ongayi kubangela ifuthe elibonakalayo kuhambiso lomqondiso. Nje ukuba ubude bomgca bungalingani, ukongeza kulungelelwaniso lwexesha, izinto eziqhelekileyo ziyafakwa kumqondiso owahlukileyo, ocutha umgangatho wesiginali kunye nokwandisa i-EMI.

Kungatshiwo ukuba owona mthetho ubalulekileyo kuyilo lokwahlulahlula i-PCB kukutshatisa ubude bomgca, kunye neminye imithetho inokuphathwa ngokuguqukayo ngokweemfuno zoyilo kunye nokusetyenziswa okusebenzayo.

Impazamo yokucinga into engeyonyani: umgca wokucinga umahluko kufuneka uxhomekeke kufutshane. Inqaku lokugcina umahluko kwimigca esondeleyo kunye ayisiyonto eyongezelelweyo ngaphandle kokunyusa ukudityaniswa kwabo, kokubini ukuphucula ukungakhuseleki kwabo kwingxolo kunye nokuthatha ithuba lokuchasana nentsimi yemagnethi ukucima ukuphazanyiswa ngumbane kwilizwe langaphandle. Nangona le ndlela intle kakhulu kwiimeko ezininzi, ayisiyiyo kwaphela. Ukuba banokukhuseleka ngokupheleleyo kungenelelo lwangaphandle, akukho mfuneko yokuba sifezekise injongo yokuchasana nokuphazamiseka kunye nokucinezelwa kwe-EMI ngokudibana okuqinileyo kunye nokunye. Uqinisekisa njani ukuba umahluko wokuhamba unendawo eyodwa kunye nokukhusela? Ukunyusa umgama phakathi kwemigca kunye neminye imiqondiso yenye yeendlela ezisisiseko. Amandla entsimi ye-electromagnetic ayancipha kunye nolwalamano lwesikwere lomgama. Ngokubanzi, xa umgama phakathi kwemigca ungaphezulu kwamaxesha ama-4 kububanzi bomgca, uphazamiseko phakathi kwawo lubuthathaka kakhulu kwaye unokungahoywa ngokusisiseko. Ukongeza, ukubekwa wedwa ngenqwelomoya emhlabeni kunokubonelela ngesiphumo esihle sokukhusela. Olu lwakhiwo luhlala lusetyenziswa kwisantya esiphezulu (ngaphezulu kwe-10G) IC yoyilo lwePCB, eyaziwa ngokuba sisakhiwo seCPW, ukuqinisekisa ngolawulo olungqongqo lwe-impedance (2Z0), i-FIG. 1-8-19.

Ukuhamba ngokungafaniyo kunokwenziwa kwimigangatho eyahlukeneyo yomqondiso, kodwa oku akukhuthazwa, kuba umahluko onje nge-impedance kunye nemingxunya kumanqanaba ahlukeneyo unokutshabalalisa umahluko wokuhambisa imowudi yokwahlula kunye nokwazisa ingxolo yemowudi eqhelekileyo. Ukongeza, ukuba ezi zimbini zikufutshane azidityaniswanga ngokuqinileyo, ukubanakho kwendlela eyahlukileyo yokumelana nengxolo kuya kuncitshiswa, kodwa i-crosstalk ayisiyongxaki ukuba isithuba esifanelekileyo sigcinwa kwindlela ejikelezileyo. Ngokubanzi rhoqo (ngezantsi kwe-GHz), i-EMI ayizukuba yingxaki enkulu. Uvavanyo lubonisa ukuba ukunciphisa amandla emitha kwimigca eyahlukileyo enomgama we-500Mils ngaphaya kwe-3 yeemitha ifikelele kwi-60dB, eyoneleyo ukuhlangabezana nomgangatho we-ELECTROMAGNETIC we-FCC. Ke ngoko, abayili akufuneki bakhathazeke kakhulu malunga nokungahambelani kombane okubangelwa kukungoneli ngokwaneleyo kwemigca eyahlukileyo.

3. inyoka

Umgca wenyoka uhlala usetyenziswa kubeko. Eyona njongo yayo kukulungelelanisa ukulibaziseka kwexesha kunye nokuhlangabezana neemfuno zoyilo lwexesha lenkqubo. Abaqulunqi kufuneka baqale baqonde ukuba ucingo lwenyoka luya kutshabalalisa umgangatho wesiginali, ukutshintsha ukulibaziseka kokuhambisa, kwaye kufuneka kuthintelwe xa kufakwa iingcingo. Nangona kunjalo, kuyilo olusebenzayo, ukuze kuqinisekiswe ukubamba okwaneleyo kweempawu, okanye ukunciphisa ixesha elisikiweyo phakathi kweqela elinye leempawu, ukubethelelwa kufuneka kwenziwe ngabom.

Ke yenza ntoni inyoka ukubonisa ukuhanjiswa? Yintoni ekufuneka ndiyihoye xa ndihamba emgceni? Ezona ndawo zimbini zibaluleke kakhulu kukudibanisa ubude (Lp) kunye nomgama wokudibanisa (S), njengoko kubonisiwe kwi-FIG. 1-8-21. Ngokucacileyo, xa isiginali sidluliselwe kumgca wenyoka, kuya kubakho ukudibana phakathi kwamacandelo emigca efanayo ngohlobo lwendlela yomahluko. I-S encinci yile, i-Lp enkulu, kwaye inqanaba lokudibanisa liya kuba lukhulu. Oku kunokubangela ukunciphisa ukulibaziseka kokuhambisa kunye nokwehla okubonakalayo kumgangatho wesiginali ngenxa yecrosstalk, njengoko kuchaziwe kwisahluko 3 sohlalutyo lwemowudi eqhelekileyo kunye nokwahluka kwendlela crosstalk.

Nazi ezinye iingcebiso zeenjineli zoLwakhiwo xa ujongene neenyoka:

1. Zama ukwandisa umgama (S) wecandelo lomgca ofanayo, ubuncinci ubuncinci kuno-3H. H ubhekisa kumgama ukusuka kumgca wesiginali ukuya kwinqwelomoya. Ngokubanzi, kukuthatha igophe elikhulu. Logama i-S inkulu ngokwaneleyo, isiphumo sokudibanisa sinokuthintelwa ngokupheleleyo.

2. Xa ubude bokudibanisa i-Lp buncitshisiwe, i-crosstalk evelisiweyo iya kufikelela kwi-saturation xa ukulibaziseka kwe-Lp kusondela kabini okanye kudlula ixesha lokunyuka komqondiso.

3. Ukulibaziseka kokuhambisa umqondiso okubangelwe lilayini efana nenyoka yomgca wokurhola okanye umgca we-Micro-strip omncinci uncinci kunowomgca omncinci. Ithiyori, umgca weribhoni awuchaphazeli inqanaba lokuhambisa ngenxa yendlela eyahlukileyo yokuhamba.

4. Isantya esiphezulu kunye nemigca yesiginali eneemfuno ezingqongqo ngexesha, zama ukungahambi ngemigca yenyoka, ngakumbi kwindawo encinci.

5. Ukuhamba kwenyoka kuyo nayiphi na iAngle kunokwamkelwa rhoqo. Ubume beC kwi-FIG. 1-8-20 inokunciphisa ngokufanelekileyo ukudibanisa phakathi komnye nomnye.

6. Kuyilo lwe-PCB olukhawulezayo, inyoka ayinakho ukubizwa ngokuba kukucoca ulwelo okanye ukungakwazi ukuphazamisa, kwaye inokunciphisa kuphela umgangatho wesiginali, ke isetyenziselwa kuphela ukuthelekisa ixesha kwaye ayikho enye injongo.

7. Ngamanye amaxesha ukujikeleza okujikelezayo kunokuqwalaselwa. Ukulinganisa kubonisa ukuba isiphumo sayo silunge ngakumbi kunamafutha aqhelekileyo okubanjwa kweenyoka.