Zvakaipa zvePCB zvechinyakare mana-layer stacking

Kana iyo interlayer capacitance isiri yakakura zvakakwana, munda wemagetsi uchagoverwa pamusoro penzvimbo yakakura yebhodhi, kuitira kuti interlayer impedance ideredzwe uye ikozvino kudzoka kunogona kuyerera ichidzokera kumusoro. Muchiitiko ichi, munda unogadzirwa nechiratidzo ichi unogona kupindira nemunda wechiratidzo chekuchinja chiri pedyo. Izvi handizvo zvataitarisira zvachose. Nehurombo, pane 4-layer board ye 0.062 inches, iwo akaparadzana ari kure uye iyo interlayer capacitance idiki.
Kana iyo wiring ichichinja kubva pachikamu 1 kuenda kuChikamu 4 kana zvinopesana, ipapo ichatungamira dambudziko iri rinoratidzwa semufananidzo.
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Iyo dhairekitori inoratidza kuti kana iyo chiratidzo ichitevera kubva pachikamu 1 kusvika kune 4 (mutsvuku mutsara), iyo yekudzoka ikozvino inofanirawo kushandura ndege (yebhuruu mutsara). Kana kuwanda kwechiratidzo kwakakwirira zvakakwana uye ndege dziri pedyo pamwe chete, ikozvino kudzoka kunogona kuyerera kuburikidza ne interlayer capacitance iripo pakati pevhu revhu uye simba remagetsi. Nekudaro, nekuda kwekushaikwa kweiyo yakananga conductive yekubatanidza yekudzoka ikozvino, nzira yekudzoka inovhiringwa, uye isu tinogona kufunga nezvekuvhiringidza uku sechipinganidzo pakati pendege inoratidzwa sepazasi mufananidzo.
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Kana iyo interlayer capacitance isiri yakakura zvakakwana, munda wemagetsi uchagoverwa pamusoro penzvimbo yakakura yebhodhi, kuitira kuti interlayer impedance ideredzwe uye ikozvino kudzoka kunogona kuyerera ichidzokera kumusoro. Muchiitiko ichi, munda unogadzirwa nechiratidzo ichi unogona kupindira nemunda wechiratidzo chekuchinja chiri pedyo. Izvi handizvo zvataitarisira zvachose. Sezvineiwo, pane 4-layer board ye 0.062 inches, iwo maseru ari kure kure (angangoita 0.020 inches), uye iyo interlayer capacitance idiki. Somugumisiro, kupindira kwemagetsi kunotsanangurwa pamusoro apa kunoitika. Izvi zvinogona kusakonzeresa kusaina kutendeseka nyaya, asi zvinozogadzira yakawanda EMI. Ichi ndicho chikonzero, kana tichishandisa cascade, isu tinodzivisa kushandura mitsara, kunyanya kune yakakwirira frequency masaini senge wachi.
Yakajairika tsika yekuwedzera decoupling capacitor padhuze neiyo transition pass gomba kuti uderedze iyo impedance inowanikwa neinodzoka ikozvino inoratidzwa sepazasi mufananidzo. Nekudaro, iyi decoupling capacitor haishande kune VHF masiginecha nekuda kwekudzikira kwayo-resonant frequency. Kune masaini eAC ane ma frequency akakwira kupfuura 200-300 MHz, isu hatigone kuvimba ne decoupling capacitors kugadzira yakaderera-impedance nzira yekudzoka. Naizvozvo, tinoda decoupling capacitor (yepasi pe200-300 MHz) uye yakati wandei interboard capacitor kune yakakwirira frequency.
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Dambudziko iri rinogona kudziviswa nekusachinja dhizaini yechiratidzo kiyi. Nekudaro, iyo diki interboard capacitance yechina-layer board inotungamira kune rimwe dambudziko rakakura: kufambisa kwemagetsi. Wachi yedhijitari ics inowanzoda hombe yenguva pfupi yemagetsi emagetsi. Sezvo kusimuka / kudonha nguva yeIC kubuda inoderera, tinoda kuendesa simba pamwero wepamusoro. Kuti tipe sosi yekuchaja, isu tinowanzoisa decoupling capacitor padyo neiyo yega logic IC. Zvisinei, pane dambudziko: kana isu tichienda mberi kwe-self-resonant frequencies, decoupling capacitors haigoni kuchengetedza uye kutamisa simba zvakanaka, nokuti pane idzi frequencies iyo capacitor ichaita senge inductor.
Sezvo maics mazhinji nhasi ane kukurumidza kusimuka / kudonha nguva (anenge 500 ps), isu tinoda imwe yekuwedzera decoupling chimiro ine yakakwirira self-resonant frequency kupfuura iyo ye decoupling capacitor. Iyo interlayer capacitance yedare redunhu inogona kuve inoshanda decoupling chimiro, chero iwo akaturikidzana ari pedyo zvakakwana kune mumwe nemumwe kuti ape yakakwana capacitance. Naizvozvo, mukuwedzera kune anowanzo shandiswa decoupling capacitors, isu tinosarudza kushandisa yakanyatso paradzana magetsi maseru uye pasi pasi kuti ipe simba renguva pfupi kune dijitari ics.
Ndokumbira utarise kuti nekuda kweyakajairwa dhizaini bhodhi kugadzira maitiro, isu kazhinji hatina matete insulators pakati pechipiri uye chechitatu akaturikidzana echina-layer board. A mana-layer board ane matete insulators pakati pechipiri neyechitatu akaturikidzana anogona kudhura zvakanyanya kupfuura akajairwa mana-layer board.