Ama-jumper capacitor noma ama-decoupling capacitor angase axazulule izinkinga ezithile, kodwa ukukhubazeka okuphelele kwama-capacitor, ama-vias, ama-pads, nezintambo kufanele kubhekwe.

Lesi sihloko sizokwethula ama-EMC PCB design ubuchwepheshe obuvela ezicini ezintathu: Isu le-PCB lendlalelo, amakhono esakhiwo kanye nemithetho yezintambo.

Isu lesendlalelo se-PCB

Ugqinsi, ngenqubo kanye nenani lezendlalelo ekwakhiweni kwebhodi lesifunda akusona isihluthulelo sokuxazulula inkinga.Ukunqwabelanisa okuhle kwezendlalelo ukuqinisekisa ukudlula nokuqaqa ibhasi lamandla futhi unciphise amandla kagesi esikhashana kungqimba lwamandla noma ungqimba lomhlabathi.Ukhiye wokuvikela inkambu ye-electromagnetic yesiginali kanye nokunikezwa kwamandla.

Ngokombono wokulandela isignali, isu elihle lokubeka izingqimba kufanele kube ukubeka yonke imikhondo yesignali kungqimba eyodwa noma eziningana, futhi lezi zendlalelo ziseduze nongqimba lwamandla noma ungqimba lomhlabathi.Ngokunikezwa kwamandla, isu elihle lokubeka izingqimba kufanele kube ukuthi ungqimba lwamandla luseduze nongqimba lomhlabathi, futhi ibanga phakathi kongqimba lwamandla kanye nongqimba lomhlabathi lincane ngangokunokwenzeka.Yilokhu esikhuluma ngesu "lokwendlalela".Ngezansi sizokhuluma ngokuqondile ngesu elihle lokubeka izingqimba le-PCB.

1. Indiza yokuqagela yesendlalelo sezintambo kufanele ibe sendaweni yesendlalelo sendiza egeleza kabusha.Uma ungqimba lwezintambo lungekho endaweni yokuqagela yongqimba lwendiza egeleza kabusha, kuzoba nemigqa yesignali ngaphandle kwendawo yokuqagela ngesikhathi sezintambo, okuzodala izinkinga "zemisebe yonqenqema", futhi kuzokwandisa indawo yeluphu yesiginali, okuzoholela ekutheni ukwanda kwemisebe yemodi ehlukile .

2. Zama ukugwema ukusetha izendlalelo zezintambo eziseduze.Ngenxa yokuthi ukulandelelwa kwesignali ehambisanayo kuzingqimba zezintambo eziseduze kungabangela i-crosstalk yesignali, uma izendlalelo zezintambo eziseduze zingenakugwenywa, isikhala sesendlalelo phakathi kwezingqimba ezimbili zezintambo kufanele sande ngokufanelekile, futhi isikhala songqimba phakathi kongqimba lwezintambo kanye nesekhethi yesignali kufanele sincishiswe.

3. Izendlalelo zendiza ezincikene kufanele zigweme ukugqagqana kwezindiza zazo.Ngoba uma ama-projection egqagqene, amandla okuhlanganisa phakathi kwezendlalelo azobangela umsindo phakathi kwezendlalelo ukuthi umbhangqwane.

I-Multilayer board design

Uma imvamisa yewashi idlula u-5MHz, noma isikhathi sokukhuphuka kwesignali singaphansi kwama-5ns, ukuze ulawule indawo yeluphu yesiginali kahle, umklamo webhodi elinezingqimba eziningi ngokuvamile uyadingeka.Izimiso ezilandelayo kufanele zinakwe lapho uklama amabhodi e-multilayer:

1. Isendlalelo sezintambo eziyisihluthulelo (isendlalelo lapho ulayini wewashi, ibhasi, ulayini wesignali yesixhumi esibonakalayo, ulayini wefrikhwensi yomsakazo, umugqa wesignali wokusetha kabusha, ulayini wesignali wokukhetha i-chip kanye nemigqa yesignali yokulawula ehlukahlukene ikhona) kufanele ibe eduze nendiza yaphansi ephelele, okungcono kakhulu. phakathi kwezindiza ezimbili eziphansi, Njengoba kuboniswe kuMfanekiso 1.

Imigqa yamasignali angukhiye ngokuvamile imisebe enamandla noma imigqa yesignali ebucayi kakhulu.Izintambo eziseduze nendiza yaphansi zinganciphisa indawo yeluphu yesiginali, kunciphise ukushuba kwemisebe noma kuthuthukise ikhono lokunqanda ukuphazamiseka.

2. Indiza yamandla kufanele ihoxiswe ngokuqhathaniswa nendiza yayo yaphansi eseduze (inani elinconyiwe 5H～20H).Ukuhlehla kwendiza yamandla ngokuhlobene nendiza yayo ebuyayo kungacindezela ngempumelelo inkinga "yemisebe emaphethelweni", njengoba kuboniswe kuMfanekiso 2.

Ngaphezu kwalokho, indiza yamandla esebenzayo eyinhloko yebhodi (indiza yamandla esetshenziswa kakhulu) kufanele ibe seduze nendiza yayo yaphansi ukuze inciphise ngokuphumelelayo indawo eyiluphu yamanje yamandla, njengoba kuboniswe kuMfanekiso 3.

3. Ukuthi awukho yini umugqa wesiginali ≥50MHz kungqimba OKUPHEZULU kanye ne-BOTTOM yebhodi.Uma kunjalo, kungcono kakhulu ukuhamba isignali yefrikhwensi ephezulu phakathi kwezingqimba ezimbili zendiza ukuze ucindezele imisebe yayo emkhathini.

Ibhodi elinongqimba olulodwa kanye nomklamo webhodi onezingqimba ezimbili

Ngokwakhiwa kwamabhodi ongqimba olulodwa kanye namabhodi anengqimba ephindwe kabili, ukuklanywa kwemigqa yesignali ebalulekile nemigqa yamandla kufanele kunakwe.Kumelwe kube nentambo ephansi eduze futhi ehambisana ne-trace yamandla ukuze kuncishiswe indawo yeluphu yamanje yamandla.

"I-Guide Ground Line" kufanele ibekwe ezinhlangothini zombili zomugqa wesiginali obalulekile webhodi elilodwa longqimba, njengoba kuboniswe kuMfanekiso 4. Umugqa wesiginali oyinhloko webhodi elinezingqimba ezimbili kufanele ube nendawo enkulu yomhlabathi endizeni yokuqagela. , noma indlela efanayo nebhodi lesendlalelo esisodwa, dweba "Umugqa Womhlaba Wokuqondisa", njengoba kuboniswe kuMfanekiso 5. "Intambo ephansi yokuqapha" ezinhlangothini zombili zomugqa wesiginali oyinhloko inganciphisa indawo ye-loop yesignali ngakolunye uhlangothi, futhi iphinde igweme ukukhuluma phakathi komugqa wesiginali neminye imigqa yesiginali.

Amakhono wesakhiwo se-PCB

Lapho uklama isakhiwo se-PCB, kufanele ugcine ngokugcwele isimiso sokuklama sokubeka umugqa oqondile eduze kwendlela yokugeleza kwesignali, futhi uzame ukugwema ukuzungeza emuva naphambili, njengoba kuboniswe kuMfanekiso 6. Lokhu kungagwema ukuhlanganisa isignali okuqondile futhi kuthinte ikhwalithi yesiginali. .

Ukwengeza, ukuze kuvinjwe ukugxambukela kanye nokuhlangana phakathi kwamasekhethi nezingxenye ze-elekthronikhi, ukubekwa kwamasekhethi kanye nokuhlelwa kwezingxenye kufanele kulandele izimiso ezilandelayo:

1. Uma isixhumi esibonakalayo "somhlaba ohlanzekile" siklanywe ebhodini, izingxenye zokuhlunga nezokuhlukanisa kufanele zibekwe ebhandeni lokuhlukanisa phakathi "kwenhlabathi ehlanzekile" nendawo yokusebenza.Lokhu kungavimbela amadivaysi okuhlunga noma okuhlukanisa ukuthi ahlangane namanye ngokusebenzisa isendlalelo seplana, esenza umphumela ube buthaka.Ngaphezu kwalokho, "emhlabathini ohlanzekile", ngaphandle kwemishini yokuhlunga nokuvikela, awekho amanye amadivaysi angabekwa.

2. Uma amasekhethi amamojula amaningi ebekwe ku-PCB efanayo, amasekhethi edijithali namasekhethi e-analog, amasekhethi anesivinini esikhulu nanesivinini esiphansi kufanele abekwe ngokwehlukana ukuze kugwenywe ukuphazanyiswa phakathi kwamasekhethi edijithali, amasekhethi e-analog, amasekhethi anesivinini esikhulu, kanye namasekhethi aphansi. - izifunda zesivinini.Ukwengeza, lapho amasekhethi aphezulu, aphakathi nendawo, kanye nesivinini esiphansi ekhona ebhodini lesifunda ngesikhathi esifanayo, ukuze kugwenywe umsindo wesekhethi wemvamisa ephezulu ekuphumeni ngaphandle ngesixhumi esibonakalayo, isimiso sokuhlela esikuMdwebo 7 kufanele sibe .

3. Isekhethi yokuhlunga yembobo yokufaka amandla yebhodi lesifunda kufanele ibekwe eduze kwesixhumi esibonakalayo ukuze kugwenywe ukuphinda kuhlanganiswe isekethe ehlungiwe.

4. Izingxenye zokuhlunga, ukuvikelwa kanye nokuhlukaniswa kwesifunda se-interface zibekwe eduze kwesixhumi esibonakalayo, njengoba kuboniswe kuMfanekiso 9, ongafinyelela ngempumelelo imiphumela yokuvikela, ukuhlunga kanye nokuzihlukanisa.Uma kukhona kokubili okokuhlunga kanye nesekhethi yokuvikela kusixhumi esibonakalayo, umgomo wokuvikela kokuqala bese ukuhlunga kufanele kube .Ngenxa yokuthi umjikelezo wokuvikela usetshenziselwa ukuqhuma kwangaphandle kanye nokucindezela okungaphezu kwamandla, uma isifunda sokuvikela sibekwe ngemva kwesifunda sokuhlunga, isifunda sokuhlunga sizolimala ngenxa ye-overvoltage kanye ne-overcurrent.

Ngaphezu kwalokho, njengoba imigqa yokufaka neyokukhiphayo yesekethe izonciphisa ukuhlunga, ukuhlukaniswa noma umphumela wokuvikela lapho ihlanganiswa nomunye nomunye, qinisekisa ukuthi imigqa yokufaka nokuphumayo yesekethe yesihlungi (isihlungi), isifunda sokuzihlukanisa nokuvikela asikwenzi. mbhangqwana nomunye ngesikhathi sokuhlela.

5. Amasekhethi azwelayo noma izingxenye (njengamasekhethi okusetha kabusha, njll.) kufanele okungenani abe kude ngamamitha ayi-1000 ukusuka kunqenqema ngalunye lwebhodi, ikakhulukazi unqenqema lwesixhumi esibonakalayo sebhodi.


6. Ukugcinwa kwamandla kanye nama-capacitor okuhlunga ama-high-frequency filter kufanele abekwe eduze kwamasekhethi amayunithi noma amadivayisi anezinguquko ezinkulu zamanje (njengamatheminali okokufaka nokukhiphayo emojula yokuphakelwa kwamandla, amafeni nama-relay) ukuze kuncishiswe indawo eyiluphu ye-current enkulu. izihibe.

7. Izingxenye zokuhlunga kufanele zibekwe eceleni ukuze kuvinjelwe isifunda esihlungiwe ukuthi singaphazanyiswa futhi.

8. Gcina amadivaysi emisebe aqinile njengamakristalu, ama-crystal oscillator, ama-relay, ukushintshanisa amandla, njll. kude nesixhumi esibonakalayo sebhodi okungenani ama-mils ayi-1000.Ngale ndlela, ukuphazamiseka kungasakazwa ngokuqondile ngaphandle noma okwamanje kungahlanganiswa nekhebuli ephumayo ukuze kukhanye ngaphandle.

I-REALTER: Ibhodi Lesifunda Eliphrintiwe, Idizayini ye-PCB, PCB Assembly