PCB elaminethiweyo uyilo uyilo umaleko umgaqo kunye nesakhiwo eqhelekileyo elaminethiweyo

Ngaphambi koyilo PCB yamanqanaba amaninzi ibhodi, umyili kufuneka aqale agqibe ubume bebhodi yesekethe esetyenziswa ngokwesikali sesekethe, ubungakanani bebhodi yesekethe kunye neemfuno zokuhambelana kwe-electromagnetic (EMC), oko kukuthi, ukwenza isigqibo sokuba asebenzise iileya ezi-4, iileya ezi-6, okanye ngaphezulu kweebhodi zeesekethe. . Emva kokumisela inani leengqimba, misela apho ubeka khona iileyile zombane zangaphakathi kunye nendlela yokusabalalisa izibonakaliso ezahlukeneyo kule miqolo. Olu lukhetho lolwakhiwo lwesitaki sePCB eninzi.

ipcb

Ubume beLaminated yimeko ebalulekileyo echaphazela ukusebenza kwe-EMC yeebhodi zePCB, kwaye ikwayindlela ebalulekileyo yokucinezela ukuphazamiseka kwe-electromagnetic. Eli nqaku lazisa umxholo ofanelekileyo we-multilayer PCB isakhiwo sebhodi.

Emva kokumisela inani lamandla, umhlaba kunye neengqimba zesiginali, ulungelelwaniso lwazo luyisihloko apho yonke injineli yePCB ayinakukuphepha;

Umgaqo jikelele wokucwangciswa komaleko:

1. Ukumisela isakhiwo se-laminated sebhodi ye-PCB eninzi, izinto ezininzi kufuneka ziqwalaselwe. Ukususela kumbono we-wiring, amanqanaba amaninzi, ngcono i-wiring, kodwa iindleko kunye nobunzima bokuvelisa ibhodi kuya kwanda. Kuba abavelisi, nokuba ulwakhiwo elaminethiweyo symmetrical okanye hayi kugxininiso ekufuneka kuqwalaselwe xa iibhodi PCB zenziwa, ngoko ke ukhetho lwenani umaleko kufuneka kuqwalaselwe iimfuno zonke iinkalo ukuphumeza ibhalansi engcono. Kubaqulunqi abanamava, emva kokugqiba i-pre-layout yamacandelo, baya kugxininisa kuhlalutyo lwe-PCB ye-wiring bottleneck. Hlanganisa kunye nezinye izixhobo ze-EDA ukuhlalutya ukuxinana kweengcingo zebhodi yesekethe; emva koko udibanise inani kunye neentlobo zemigca yomqondiso kunye neemfuno ezikhethekileyo zocingo, njengemigca yokwahlukana, imigca yesignali ebuthathaka, njl. ngoko ngokohlobo lonikezelo lwamandla, ukuhlukaniswa kunye nokuchasana nokuphazamiseka Iimfuno zokumisela inani leengqimba zombane zangaphakathi. Ngale ndlela, inani leengqimba zebhodi yesekethe yonke imiselwe ngokusisiseko.

2. I-bottom of the component surface (uluhlu lwesibini) luyi-plane yomhlaba, ebonelela ngesixhobo sokukhusela isixhobo kunye nendiza yokubhekisela kwi-wiring ephezulu; umaleko wesignali onovakalelo kufuneka ube kufuphi nommandla wombane wangaphakathi (amandla angaphakathi / umaleko womhlaba), usebenzisa umaleko omkhulu wangaphakathi wombane weCopper film ukubonelela ngokukhusela umaleko wesiginali. Umaleko wokuhambisa umqondiso wesantya esiphezulu kwisekethe kufuneka ube ngumaleko ophakathi wesiginali kwaye ufakwe phakathi kweeleya ezimbini zangaphakathi zombane. Ngale ndlela, ifilimu yobhedu yemigangatho emibini yangaphakathi yombane inokubonelela ngokhuseleko lwe-electromagnetic yokuhanjiswa kwesantya esiphezulu, kwaye kwangaxeshanye, inokunciphisa ngokufanelekileyo ukusasazeka kwemitha yesantya esiphezulu phakathi kwamaleko amabini angaphakathi ombane ngaphandle kokubangela ukuba kuthintelwe ukusasazeka kwemitha yesantya esiphezulu. ukuphazamiseka kwangaphandle.

3. Zonke iileyile zesignali zisondele kangangoko kunokwenzeka kwinqwelomoya ephantsi;

4. Zama ukuphepha iileya ezimbini zesignali ezijongene ngqo kwenye; kulula ukwazisa i-crosstalk phakathi kweengqimba zesignali ezikufutshane, okubangela ukusilela komsebenzi wesekethe. Ukongeza inqwelomoya ephantsi phakathi kweengqimba ezimbini zeempawu kunokuphepha ngokufanelekileyo i-crosstalk.

5. Umthombo wamandla oyintloko usondele kakhulu kuwo ngokuhambelanayo;

6. Thatha ingqalelo i-symmetry yesakhiwo se-laminated.

7. Kumaleko we-motherboard, kunzima kwii-motherboards ezikhoyo ukulawula i-wiring ye-wiring emide. Kwi-frequency yokusebenza kwinqanaba lebhodi ngaphezulu kwe-50MHZ (jonga imeko engaphantsi kwe-50MHZ, nceda uphumle ngokufanelekileyo), kuyacetyiswa ukuba ulungiselele umgaqo:

Umphezulu wecandelo kunye ne-welding surface yi-plane yomhlaba epheleleyo (ikhaka);Akukho zingqimba ze-wiring ezikufutshane ezihambelanayo;Zonke iileya zesignali zisondele kangangoko kunokwenzeka kwi-plane yomhlaba;

Isignali engundoqo isecaleni komhlaba kwaye ayigqithisi isahlulo.

Qaphela: Xa ucwangcisa iileya zePCB ezithile, le migaqo ingentla kufuneka ibhetyebhetye ibe yinkosi. Ngokusekelwe ekuqondeni le migaqo ingentla, ngokweemfuno ezichanekileyo zebhodi enye, njengale: ingaba i-wiring layer, unikezelo lwamandla, ulwahlulo lwendiza yomhlaba luyafuneka, njl. ungayikhupheli nje ngokuphandle, okanye ubambelele kuyo.

8. Iingqimba zombane zangaphakathi ezininzi ezisekelwe phantsi zinokunciphisa ngokufanelekileyo i-impedance yomhlaba. Ngokomzekelo, i-signal layer ye-A kunye ne-signal layer ye-B isebenzisa iindiza ezihlukeneyo zomhlaba, ezinokunciphisa ngokufanelekileyo ukuphazamiseka kwemowudi eqhelekileyo.

Isakhiwo esiqhelekileyo esisetyenziswayo: ibhodi ye-4-layer

Oku kulandelayo kusebenzisa umzekelo webhodi ye-4-layer ukubonisa indlela yokuphucula ukulungiswa kunye nokudibanisa kwezakhiwo ezahlukeneyo ze-laminated.

Kwiibhodi ezisetyenziswa ngokuqhelekileyo ezi-4, kukho iindlela zokupakisha ezilandelayo (ukusuka phezulu ukuya phezulu).

(1) Siganl_1 (Phezulu), GND (Inner_1), AMANDLA (Inner_2), Siganl_2 (Ezantsi).

(2) Siganl_1 (Phezulu), AMANDLA (Inner_1), GND (Inner_2), Siganl_2 (Ezantsi).

(3) AMANDLA (Phezulu), Siganl_1 (Inner_1), GND (Inner_2), Siganl_2 (Ezantsi).

Ngokucacileyo, uKhetho lwesi-3 luswele ukudityaniswa okusebenzayo phakathi komgangatho wamandla kunye nomaleko osemhlabeni kwaye akufuneki kwamkelwe.

Ngoko ke kufuneka kukhethwe njani ukhetho loku-1 nolwesi-2?

Under normal circumstances, designers will choose option 1 as the structure of the 4-layer board. The reason for the choice is not that Option 2 cannot be adopted, but that the general PCB board only places components on the top layer, so it is more appropriate to adopt Option 1.

Kodwa xa amacandelo kufuneka abekwe kuzo zombini iileyile eziphezulu kunye nezantsi, kunye nobukhulu be-dielectric phakathi komgangatho wamandla angaphakathi kunye nomgangatho womhlaba mkhulu kwaye ukudibanisa kubi, kuyimfuneko ukuqwalasela ukuba yeyiphi i-layer enemigca embalwa yesignali. KuKhetho loku-1, kukho imigca yesignali embalwa kumaleko asezantsi, kwaye ifilimu yobhedu yendawo enkulu ingasetyenziselwa ukudibanisa kunye ne-MOWER layer; ngokuchaseneyo, ukuba amacandelo ahlelwe ngokukodwa kwinqanaba elisezantsi, iKhetho yesi-2 kufuneka isetyenziswe ukwenza ibhodi.

Ukuba ulwakhiwo lwe-laminated luyamkelwa, umaleko wamandla kunye nomgangatho womhlaba sele udibene. Ukuqwalasela iimfuno ze-symmetry, iskimu 1 samkelwa ngokubanzi.

Ibhodi ye-6-layer

Emva kokugqiba uhlalutyo lwesakhiwo se-laminated ye-4-layer board, oku kulandelayo kusetyenziswa umzekelo webhodi ye-6-layer ukudibanisa ukubonisa ukulungelelaniswa kunye nokudibanisa ibhodi ye-6 kunye nendlela ekhethiweyo.

(1) Siganl_1 (Phezulu), GND (Inner_1), Siganl_2 (Inner_2), Siganl_3 (Inner_3), amandla (Inner_4), Siganl_4 (Ezantsi).

Isisombululo se-1 sisebenzisa i-4 yeempawu zeempawu kunye ne-2 yangaphakathi yamandla / imigangatho yomhlaba, kunye neengqimba ezininzi zesignali, ezihambelana nomsebenzi we-wiring phakathi kwamacandelo, kodwa iziphene zesi sisombululo nazo zibonakala ngakumbi, ezibonakaliswa kule miba mibini ilandelayo:

① Inqwelomoya yamandla kunye nenqwelomoya ephantsi ziqelelene, kwaye azidityaniswanga ngokwaneleyo.

② Uluhlu lwesignali Siganl_2 (Inner_2) kunye ne-Siganl_3 (Inner_3) zihambelana ngokuthe ngqo, ngoko ukuhlukaniswa kwesignali akulungile kwaye i-crosstalk kulula ukwenzeka.

(2) Siganl_1 (Phezulu), Siganl_2 (Inner_1), AMANDLA (Inner_2), GND (Inner_3), Siganl_3 (Inner_4), Siganl_4 (Ezantsi).

ISkimu 2 xa kuthelekiswa nesikimu 1, umaleko wamandla kunye nenqwelomoya yomhlaba zidityaniswe ngokupheleleyo, enenzuzo ethile phezu kwesikimu 1, kodwa

I-Siganl_1 (Phezulu) kunye ne-Siganl_2 (Inner_1) kunye ne-Siganl_3 (Inner_4) kunye ne-Siganl_4 (Ezantsi) izingqimba zesignali zihambelana ngokuthe ngqo komnye nomnye. Ukwahlukaniswa komqondiso akulunganga, kwaye ingxaki ye-crosstalk ayisonjululwa.

(3) Siganl_1 (Phezulu), GND (Inner_1), Siganl_2 (Inner_2), AMANDLA (Inner_3), GND (Inner_4), Siganl_3 (Ezantsi).

Xa kuthelekiswa neNkqubo yoku-1 kunye neNkqubo yesi-2, iNkqubo yesi-3 inomaleko womqondiso omnye onganeno kunye nolunye umaleko wangaphakathi wombane. Nangona iileya ezikhoyo zocingo zincitshisiwe, esi sikimu sisombulula iziphene eziqhelekileyo zeSkimu 1 kunye neSikimu 2.

① Inqwelomoya yamandla kunye nenqwelomoya ephantsi zidityaniswe ngokuqinileyo.

② Umaleko ngamnye wesignali uhambelana ngokuthe ngqo nombane ongaphakathi, kwaye uhlukaniswe ngokufanelekileyo kwezinye iileyile zesignali, kwaye i-crosstalk ayilula ukwenzeka.

③ Siganl_2 (Inner_2) ikufuphi nemigangatho emibini yangaphakathi yombane ye-GND (Inner_1) kunye ne-MANDLA (Inner_3), engasetyenziselwa ukuhambisa izibonakaliso zesantya esiphezulu. Imigangatho emibini yangaphakathi yombane inokukhusela ngokufanelekileyo ukuphazamiseka kwihlabathi langaphandle ukuya kwi-Siganl_2 (Inner_2) layer kunye nokuphazamiseka kweSiganl_2 (Inner_2) kwihlabathi langaphandle.

Kuyo yonke imiba, iskimu 3 ngokucacileyo sesona siphuculwe kakhulu. Ngelo xesha, iskimu sesi-3 sikwasetyenziswa ngokuqhelekileyo isakhiwo se-laminated kwiibhodi ezi-6. Ngokuhlalutya le mizekelo mibini ingentla, ndikholelwa ukuba umfundi unokuqonda okuthile kwesakhiwo se-cascade, kodwa kwezinye iimeko, iskimu esithile asikwazi ukuhlangabezana nazo zonke iimfuno, ezifuna ukuqwalaselwa kokuphambili kwemigaqo yoyilo eyahlukeneyo. Ngelishwa, ngenxa yokuba ibhodi yesekethe uyilo umaleko inxulumene ngokusondeleyo neempawu zesekethe yokwenyani, ukusebenza anti-ukuphazamiseka kunye noyilo kugxininiso lweesekethe ezahlukeneyo yahlukile, ngoko ke eneneni le migaqo akukho ephambili ezimiseleyo ireferensi. Kodwa into eqinisekileyo kukuba umgaqo woyilo wesi-2 (umgangatho wamandla wangaphakathi kunye nomgangatho womhlaba kufuneka udityaniswe ngokuqinileyo) kufuneka udityaniswe kuqala kuyilo, kwaye ukuba iimpawu zesantya esiphezulu kufuneka zihanjiswe kwisekethe, ngoko umgaqo woyilo 3 (umaleko wogqithiso lwesantya esiphezulu sophawu kwisekethe) Kufuneka ibe luphawu oluphakathi kwaye lufakwe phakathi kweeleya ezimbini zangaphakathi zombane) kufuneka zaneliswe.

Ibhodi ye-10-layer

PCB eqhelekileyo-10- umaleko ibhodi uyilo

Ulandelelwano lweingcingo ngokubanzi yi-TOP–GND— umaleko womqondiso— umaleko wamandla—GND— umaleko wophawu— umaleko wamandla— umaleko wesiginali—GND—BOTTOM

Ukulandelelana kwe-wiring ngokwayo akuqinisekanga, kodwa kukho imigangatho kunye nemigaqo yokuyithintela: Ngokomzekelo, iileyile ezikufutshane zoluhlu oluphezulu kunye nomgangatho ophantsi zisebenzisa i-GND ukuqinisekisa iimpawu ze-EMC zebhodi enye; umzekelo, umaleko wesignali ngamnye ukhetha ukusebenzisa umaleko we-GND njengeNdlela yokubhekisela; unikezelo lwamandla olusetyenziswa kuyo yonke ibhodi enye lubekwe ngokukhethekileyo kwiqhekeza lonke lobhedu; ukuchaphazeleka, isantya esiphezulu, kwaye sikhetha ukuhamba kunye nomaleko wangaphakathi wokutsiba, njl.