Mukugadzirwa kwePCB, kuenderana kwemagetsi (EMC) uye kukanganiswa kwemagetsi (EMI) kwagara kuri matambudziko maviri akakonzeresa kuti mainjiniya aite musoro, kunyanya mudhizaini yanhasi yedunhu redhizaini uye kurongedza kwechikamu kuri kudzikira, uye maOEM anoda yepamusoro-kumhanya masisitimu Mamiriro.

1. Crosstalk uye wiring ndiwo mapoinzi akakosha

Iyo wiring inonyanya kukosha kuve nechokwadi chekuyerera kwemazuva ese. Kana iyo ikozvino ichibva kune oscillator kana chimwe chigadziri chakafanana, zvinonyanya kukosha kuchengetedza ikozvino yakaparadzana nendege yepasi, kana kusarega ikozvino ichimhanya ichienderana kune imwe tsvakiridzo. Maviri akaenzana akakwira-kumhanya masaini anoburitsa EMC uye EMI, kunyanya crosstalk. Nzira yekupikisa inofanira kunge iri pfupi, uye nzira yekudzoka ikozvino inofanira kuva pfupi sezvinobvira. Hurefu hwenzira yekudzoka hunofanira kufanana nehurefu hwekutumira.

Kune EMI, imwe inonzi "infringed wiring" uye imwe yacho "victimized wiring". Iko kubatanidzwa kwe inductance uye capacitance kuchakanganisa "akabatwa" trace nekuda kwekuvapo kwemagetsi emagetsi, nekudaro achigadzira kumberi nekudzosera kumashure mafungu pa "victim trace". Muchiitiko ichi, ripples ichagadzirwa munzvimbo yakagadzikana apo kureba kwekutumira uye kureba kwekugamuchira kwechiratidzo kunenge kwakaenzana.

Munzvimbo yakanyatsogadzikana uye yakagadzikana ye wiring, iyo induced currents inofanira kukanzura mumwe nemumwe kunze kubvisa crosstalk. Zvisinei, tiri munyika ine vanhu vasina kukwana, uye zvinhu zvakadaro hazvisati zvichizoitika. Naizvozvo, chinangwa chedu ndechekuchengeta crosstalk yeese traces kuita shoma. Kana hupamhi pakati pemitsara inofananidzwa yakapetwa kaviri upamhi hwemitsara, mhedzisiro yecrosstalk inogona kudzikiswa. Semuyenzaniso, kana hupamhi hwekuronda huri 5 mils, nhambwe yediki pakati pematanho maviri anoenderana anomhanya anofanira kunge ari mamirimita gumi kana kudarika.

Sezvo zvinhu zvitsva uye zvinhu zvitsva zvichiramba zvichionekwa, vagadziri vePCB vanofanirwa kuenderera mberi nekutarisana nemagetsi emagetsi uye nyaya dzekuvhiringidza.

2. Decoupling capacitor

Decoupling capacitors inogona kuderedza yakashata mhedzisiro yecrosstalk. Iwo anofanirwa kunge ari pakati pepini yekupa magetsi uye pini yepasi yechishandiso kuve nechokwadi yakaderera AC impedance uye kuderedza ruzha uye crosstalk. Kuti uwane yakaderera impedance pane yakafara frequency renji, akawanda decoupling capacitors anofanirwa kushandiswa.

Nheyo yakakosha yekuisa decoupling capacitors ndeyekuti iyo capacitor ine diki capacitance kukosha inofanira kunge iri padyo sezvinobvira kune mudziyo kuti uderedze inductance mhedzisiro pakutsvaga. Iyi chaiyo capacitor iri padyo sezvinobvira kune pini yemagetsi kana simba rekutsvaga remudziyo, uye batanidza padhi ye capacitor zvakananga kune via kana pasi ndege. Kana tsvakiridzo yacho yakarebesa, shandisa nzira dzakawanda kudzikisira pasi impedance.

3. Gadzira PCB

Nzira yakakosha yekudzikisa EMI kugadzira iyo PCB pasi ndege. Danho rekutanga nderekuita kuti nzvimbo yepasi ive yakakura sezvinobvira mukati menzvimbo yakazara yePCB redunhu bhodhi, iyo inogona kuderedza emission, crosstalk uye ruzha. Kunyatsotarisirwa kunofanira kutorwa paunenge uchibatanidza chikamu chimwe nechimwe kunzvimbo yepasi kana ndege yepasi. Kana izvi zvikasaitwa, iyo neutralizing mhedzisiro yeyakavimbika pasi ndege haizoshandiswe zvizere.

Iyo yakanyanya kuomarara PCB dhizaini ine akati wandei akagadzikana voltages. Nenzira yakanaka, imwe neimwe yereferensi voltage ine yayo inoenderana pasi ndege. Nekudaro, kana iyo pasi pasi yakawandisa, ichawedzera mutengo wekugadzira wePCB uye kuita kuti mutengo uwedzere. Chibvumirano ndechekushandisa ndege dzepasi munzvimbo nhatu kusvika shanu dzakasiyana, uye imwe neimwe ndege yepasi inogona kuva nezvikamu zvakawanda zvepasi. Izvi hazvidzore chete mutengo wekugadzira wedunhu redunhu, asi zvakare zvinoderedza EMI neEMC.

Kana iwe uchida kudzikisa EMC, yakaderera impedance grounding system yakakosha. Mune akawanda-layer PCB, zviri nani kuve neakavimbika pasi ndege, pane kuba mhangura kana yakapararira pasi ndege, nekuti ine yakaderera impedance, inogona kupa yazvino nzira, ndiyo yakanakisa reverse chiratidzo sosi.

Hurefu hwenguva iyo chiratidzo ichidzokera pasi zvakare yakakosha zvikuru. Iyo nguva iri pakati pechiratidzo neyechiratidzo sosi inofanirwa kuenzana, zvikasadaro inoburitsa antenna-senge chiitiko, ichiita iyo radiated simba chikamu cheEMI. Saizvozvo, zviteshi zvinoendesa ikozvino kune / kubva kune iyo chiratidzo sosi inofanira kunge ipfupi sezvinobvira. Kana kureba kwenzira yekubuda uye nzira yekudzoka isina kuenzana, kubvongodzwa kwepasi kuchaitika, izvo zvinozoitawo EMI.

4. Dzivisa 90 ° angle

Kuti uderedze EMI, dzivirira waya, vias uye zvimwe zvikamu zvinogadzira 90 ° angle, nekuti makona ekurudyi anoburitsa mwaranzi. Pakona ino, iyo capacitance ichawedzera, uye iyo hunhu impedance ichachinja zvakare, ichitungamira kune kuratidzwa uyezve EMI. Kuti udzivise makona 90°, mitsvairo inofanirwa kufambiswa kumakona angangoita maviri 45° makona.

5. Shandisa vias nekungwarira

Munenge ose PCB marongerwo, vias anofanira kushandiswa kupa conductive kubatana pakati siyana akaturikidzana. PCB dhizaini mainjiniya anofanirwa kungwarira nekuti vias inoburitsa inductance uye capacitance. Mune zvimwe zviitiko, ivo vanozoburitsawo maratidziro, nekuti iyo hunhu impedance inoshanduka kana via pakaitwa mukuteedzera.

Uyewo yeuka kuti vias achawedzera kureba mucherechedzo uye vanoda kufananidzwa. Kana iri mutsauko wekutsvaga, vias inofanira kudzivirirwa zvakanyanya sezvinobvira. Kana isingakwanise kudziviswa, shandisa vias mune ese maviri matera kutsiva kunonoka muchiratidzo uye nzira yekudzoka.

6. Cable uye kudzivirirwa kwemuviri

Makombora anotakura maseketi edhijitari uye analog currents anoburitsa parasitic capacitance uye inductance, zvichikonzera matambudziko mazhinji ane chekuita neEMC. Kana tambo yakamonyoroka-peiri ikashandiswa, iyo coupling level ichachengetwa yakaderera uye inogadzirwa magineti inobviswa. Kune ma-high-frequency masaini, tambo yakadzivirirwa inofanirwa kushandiswa, uye kumberi nekumashure kwetambo kunofanirwa kudzikwa kuti ibvise kukanganiswa kweEMI.

Kudzivirira muviri ndeyekuputira yese kana chikamu chesisitimu nesimbi pasuru kudzivirira EMI kupinda muPCB wedunhu. Idzi mhando yekudzivirira yakafanana neyakavharika yakadzika conductive mudziyo, iyo inoderedza antenna loop saizi uye inobata EMI.