Ngoyilo lomngxuma we-HDI PCB
Kuyilo lwe-PCB olunesantya esiphezulu, i-PCB enamaleko amaninzi isoloko isetyenziswa, kwaye ngomngxuma yinto ebalulekileyo kuyilo lwePCB enamaleko amaninzi. Umngxuma ophumela kwi-PCB ubukhulu becala uqulunqwe ngamalungu amathathu: umngxuma, indawo yephedi yokuwelda ejikeleze umngxuma kunye nommandla wokwahlula waMANDLA. Okulandelayo, siya kuqonda isantya esiphezulu sePCB ngengxaki yomngxuma kunye neemfuno zoyilo.
Impembelelo yomngxuma kwi-HDI PCB
Kwibhodi ye-multilayer ye-HDI PCB, uqhagamshelwano phakathi kolunye umaleko kunye nomnye kufuneka ludityaniswe ngemingxunya. Xa i-frequency ingaphantsi kwe-1 GHz, imingxuma inokudlala indima efanelekileyo ekudibaniseni, kwaye i-parasitic capacitance kunye ne-inductance inokungahoywa. Xa i-frequency iphezulu kune-1 GHz, umphumo we-parasitic we-over-hole kwimfezeko yesignali ayinakuhoywa. Ngeli xesha, umngxuma ongaphezulu ubonisa i-impedance engapheliyo kwindlela yokuhambisa, eya kukhokelela ekubonakalisweni komqondiso, ukulibaziseka, ukuthotywa kunye nezinye iingxaki zengqibelelo yomqondiso.
Xa umqondiso ugqithiselwa komnye umaleko ngomngxuma, umaleko wesalathiso womgca wesignali usebenza njengendlela yokubuya yesignali ngomngxuma, kwaye imbuyekezo yangoku iya kuhamba phakathi kweereferensi zereferensi ngokusebenzisa i-capacitive coupling, ibangela iibhombu zomhlaba kwaye ezinye iingxaki.
Uhlobo loMngxuma onguNongo, Ngokubanzi, ngomngxuma wohlulwe ngokweendidi ezintathu: ngomngxuma, umngxuma oyimfama kunye nomngxuma ongcwatywe.
Umngxuma oyimfama: umngxuma obekwe phezulu nasezantsi kwibhodi yesekethe eprintiweyo, enobunzulu obuthile bokudibanisa phakathi komgca womphezulu kunye nomgca wangaphakathi ongaphantsi. Ubunzulu bomngxuma ngokuqhelekileyo abugqithisi umlinganiselo othile we-aperture.
Umngxuma ongcwatywayo: umngxuma wokudityaniswa kwinqanaba elingaphakathi lebhodi yesekethe eprintiweyo engagqithiseli kumphezulu webhodi yesekethe.
Ngomngxuma: lo mngxuma udlula kuyo yonke ibhodi yesekethe kwaye ingasetyenziselwa uqhagamshelo lwangaphakathi okanye njengendawo yokubeka indawo yamacandelo. Ngenxa yokuba umngxunya kwinkqubo kulula ukufikelela kuyo, ixabiso liphantsi, ngoko ke ibhodi yesekethe eprintiweyo ngokubanzi isetyenziswa.
Ngoyilo lomngxuma kwi-PCB enesantya esiphezulu
Kuyilo lwePCB olunesantya esiphezulu, umngxuma we-VIA obonakala ulula uya kuhlala uzisa iziphumo ezingalunganga kuyilo lwesekethe.Ukuze unciphise iziphumo ezibi ezibangelwa yimpembelelo yeparasite yokugqobhoza, sinokuzama konke okusemandleni ethu uku:
(1) khetha ubungakanani obufanelekileyo bomngxuma. Kuyilo lwePCB olunoxinaniso olunamanqanaba amaninzi, kungcono ukhethe i-0.25mm/0.51mm/0.91mm (umngxuma wokubhobhoza/i-welding pad/Indawo yokuzahlula AMANDLA) ngomngxuma. Uxinaniso lwePCB lunokusebenzisa i-0.20mm/0.46mm/0.86mm ngomngxuma, lungazama nokungaphumeleli umngxuma; Kuba unikezelo lwamandla okanye umngxuma wocingo osemhlabeni unokuqwalaselwa ukusebenzisa ubungakanani obukhulu ukunciphisa i-impedance;
(2) ubukhulu bendawo yokwahlula AMANDLA, kokukhona kungcono. Ukuqwalasela ukuxinana komngxuma ophumela kwi-PCB, ngokuqhelekileyo nguD1=D2+0.41;
(3) zama ukungawutshintshi umaleko womqondiso kwiPCB, oko kukuthi, zama ukunciphisa umngxuma;
(4) ukusetyenziswa kwePCB ebhityileyo inceda ekunciphiseni iiparamitha ezimbini zeparasitic ngomngxuma;
(5) isikhonkwane sonikezelo lwamandla kunye nomhlaba kufuneka ube kufutshane nomngxuma. I-short lead phakathi komngxuma kunye nepini, ingcono, kuba iya kukhokelela ekwandeni kwe-inductance.Ngexesha elifanayo, ukunikezelwa kwamandla kunye nokukhokela komhlaba kufuneka kube nzima ngokusemandleni ukunciphisa i-impedance;
(6) beka iindawo zokudlula ezisezantsi kufutshane nemingxuma yokudlula yomaleko wotshintshiselwano lomqondiso ukubonelela ngomgama omfutshane welophu yomqondiso.
Ukongeza, ngokusebenzisa ubude umngxuma kwakhona yenye yezinto eziphambili ezichaphazela ngokusebenzisa umngxuma inductance.Kuba umngxuma umngxuma phezulu nasezantsi, ukudlula umngxuma ubude ilingana PCB ubukhulu. Ngenxa yokwanda kwenani leeleya zePCB, ubukhulu bePCB buhlala bufikelela ngaphezu kwe-5 mm.
Nangona kunjalo, kwi-high-speed PCB design, ukwenzela ukunciphisa ingxaki ebangelwa ngumngxuma, ubude bomngxuma bulawulwa ngokubanzi ngaphakathi kwe-2.0mm. Kuba ubude bomngxuma omkhulu kune-2.0mm, ukuqhubeka kwe-impedance yomngxuma kunokuphuculwa kwezinye. ubungakanani ngokunyusa i-diameter yomngxuma.Xa ubude bomngxuma wokutyhutyha yi-1.0mm nangaphantsi, owona mngxuma wokuphumela kwi-0.20mm ~ 0.30mm.