One Basic concept ye perforation

Kuburikidza neburi (VIA) chikamu chakakosha che Multilayer pcb, uye mutengo wemakomba ekuchera unowanzo kuve 30% kusvika 40% yemutengo wePBB board board inogadzira. Zvichitaurwa zviri nyore, gomba rega rega paPCB rinogona kunzi pfuuri gomba. Panyaya yekushanda, gomba rinogona kukamurwa muzvikamu zviviri: imwe inoshandiswa yekubatanidza magetsi pakati pezvikamu; Imwe yacho inoshandiswa kugadzirisa dhizaini kana kuisa panzvimbo. Mukutaura kwemaitiro, aya maburi-anoburitswa anowanzo kuve akapatsanurwa muzvikamu zvitatu, zvinoti bofu kuburikidza, kuvigwa kuburikidza nekupfuura nepakati. Makomba mapofu ari kumusoro nepamusoro ezasi ePRINTED wedunhu bhodhi uye ane humwe hudzamu hwekubatanidza pamusoro wedunhu kune yemukati redunhu pazasi. Kudzika kwemakomba kazhinji hakupfuure imwe chiyero (kuzarura). Maburi akavigwa maburi ekubatanidza mukati mechikamu chemukati chebhodhi redunhu rakadhindwa risingatambanuke kusvika pamusoro pebhodhi redunhu rakadhindwa. Iwo marudzi maviri emaburi ari mukati mechikamu chemukati chebhodhi redunhu, iro rinozadzikiswa neiyo yeku-gomba yekuumba maitiro isati yadzvanywa, uye akaturikidzana akati wandei mukati anogona kugadzirwa panguva yekuumbwa kweiyo-yegomba. Rudzi rwechitatu, rwunonzi kuburikidza-maburi, runomhanya nemudunhu rese redunhu uye runogona kushandiswa mukubatana kwemukati kana sekumisikidza nekutsvaga maburi ezvinhu. Nekuti iro gomba riri nyore kushandisa mukuita, mutengo wakaderera, saka mazhinji akadhindwa wedunhu mabhodhi anoishandisa, pane mamwe maviri marudzi ekupfuura nepaburi. Izvi zvinotevera kuburikidza nemakomba, pasina tsananguro yakasarudzika, ichaonekwa sekunge kuburikidza nemakomba.

Pcbp kuburikidza mugomba inokosha pfungwa uye kuburikidza mugomba nzira sumo

Kubva pane dhizaini yekuona, iyo-yegomba-inowanzo kuve inoumbwa nezvikamu zviviri, imwe igomba rekuboora riri pakati, uye imwe nzvimbo yepad yakatenderedza gomba rekuboora. Hukuru hwezvikamu zviviri izvi hunosarudza hukuru hwepakati-buri. Zviripachena, mukugadzirwa kweiyo-kumhanya-kumhanya, yakakwira-density PCB, iyo dhizaini inogara ichida kuti gomba riite diki sezvinobvira, uyu muyenzaniso unogona kusiya yakawanda wiring nzvimbo, uyezve, idiki gomba, iro rayo parasite capacitance idiki, zvimwe inokodzera yedhijidhi-inomhanya. Asi kuderedzwa kwegomba panguva imwechete kunounza kuwedzera kwemutengo, uye saizi yegomba haigone kudzikiswa pasina muganho, inogumira nekuchera (drill) uye plating (plating) uye imwe tekinoroji: iyo diki gomba, the yakareba iyo nguva inotora kubaya, zviri nyore zviri kutsauka kubva panzvimbo yepakati; Kana iko kudzika kwegomba kuri kudarika ka6 dhayamita yegomba, hazvigoneke kuvimbisa yunifomu yendarira yakanamirwa pamadziro egomba. Semuyenzaniso, kana ukobvu (kuburikidza-mugomba kudzika) kweyakajairika-nhete-pcb bhodhi iri 6Mil, ipapo hushoma mugomba dhayamita iyo pcb vagadziri vanogona kupa ndeye 50Mil. Nekuvandudzwa kwelaser drilling tekinoroji, saizi yekuchera inogona zvakare kuve idiki uye idiki. Kazhinji, iyo dhayamita yegomba iri shoma kana kuti yakaenzana ne6Mils, isu tinoiti micro hole. Microholes inowanzoshandiswa muHDI (yakakwirira density Interconnect chimiro) dhizaini. Microhole tekinoroji inobvumira kuti gomba rirohwe zvakananga padhi (VIA-in-pad), iyo inovandudza zvakanyanya kuita kwedunhu uye inochengetedza wiring nzvimbo.

Iyo yekupfuura-gomba pamutsetse wekutepfenyura ndiyo nzvimbo yekumira yeiyo impedance discontinuity, iyo inokonzeresa kuratidzwa kwechiratidzo. Kazhinji, iyo impedance yakaenzana yeburi-gomba inenge 12% yakaderera pane iyo yetambo yekufambisa. Semuenzaniso, iyo impedance yeiyo 50ohm yekufambisa tambo inodzikira ne6 ohm painopfuura nepaburi-gomba (iyo yakanangana zvakare inoenderana nesaizi yepasiti-gomba uye ukobvu hweplate, asi kwete kuderera zvachose). Nekudaro, iko kuratidzwa kunokonzerwa nekumiswa kwemhedheni kuburikidza negomba iri iri diki kwazvo, uye kuenzanisa kwayo kwekuratidzira kuri chete: (44-50) / (44 + 50) = 0.06. Zvinetso zvinokonzerwa nehunza zvakanyanya kutariswa pesvedzero yehutachiona capacitance uye inductance.

Chisvetasimba capacitance uye inductance kuburikidza mugomba

Icho chisvetasimba chakarasika capacitance chiripo mugomba chairo. Kana iyo dhayamita yenzvimbo yekumiririra yekumwena yegomba pane yakagadzikwa iri D2, iyo dhayamita yemoto padhi ndeye D1, ukobvu hwePCB bhodhi ndiT, uye dielectric inogara iripo yeiyo substrate iri ε, iyo tupukanana capacitance gomba iri rinenge C = 1.41εTD1 / (D2-D1).

Mhedzisiro huru yehutachiona capacitance padunhu ndeyekuwedzera iyo nguva yekukwira kwechiratidzo uye nekudzora kumhanya kwedunhu. Semuenzaniso, kune pcb board ine ukobvu hwe50Mil, kana hupamhi hwepakati-gomba padhi iri 20Mil (hupamhi hwechibhorani chiri 10Mils) uye dhayamita yeiyo solder block ndeye 40Mil, tinogona kufungidzira hutachiona hwehutachiona hwe iyo-iyo-gomba nefomula iri pamusoro: C = 1.41 × 4.4 × 0.050 × 0.020/ (0.040-0.020) = 0.31pF shanduko yenguva yekusimuka inokonzerwa ne capacitance inosvika seizvi: T10-90 = 2.2c (Z0 / 2) = 2.2 × 0.31x (50/2) = 17.05ps Kubva pamitengo iyi, zvinogona kuoneka kuti kunyangwe hazvo simba rekukwira kunonoka uye kunonoka zvichikonzerwa nehutachiona hwekugona kweimwe kuburikidza- gomba harinyatso kuoneka, kana iyo-iyo-gomba ichishandurwa pakati pezvikamu kakawanda, akawanda kuburikidza-maburi anoshandiswa. Ngwarira mukugadzira kwako. Mukuita dhizaini, parasitic capacitance inogona kuderedzwa nekuwedzera chinhambwe pakati pegomba nenzvimbo yekuisa mhangura (anti-pad) kana nekudzikisa dhayamita repadhi. Muchigadziro chepamusoro-speed digital circuit, iyo parasitic inductance ye kuburikidza-gomba inokuvadza kupfuura iyo yeparasitic capacitance. Yayo parasitic nhepfenyuro inductance inonetesa mupiro wekudarika capacitance uye kudzora kusefa kugona kwesimba rese system. Isu tinogona kungoverenga iyo parasitic inductance yekupfuura-gomba kufungidzira tichishandisa inotevera empirical formula: L=5.08h [ln (4h/d) +1]

Apo L inoreva kudhonzwa kwegomba, H ndiko kureba kwegomba, uye D ndiyo dhayamita yegomba repakati. Inogona kuonwa kubva kuiyo equation kuti hupamhi hwegomba hune hunyanzvi pane iyo inductance, nepo hurefu hwegomba huine simba rakanyanya pane inductance. Ndichiri kushandisa iri pamusoro muenzaniso, iyo inductance kunze kwegomba inogona kuverengerwa se:

L = 5.08 × 0.050 [ln (4 × 0.050 / 0.010) +1] = 1.015nh Kana nguva yekumuka kwechiratidzo iri 1ns, saka saizi yemedance yakaenzana ndeiyi: XL = πL / T10-90 = 3.19 ω. Iyi impedance haigone kufuratirwa muhupo hweakakwira frequency yazvino. Kunyanya, iyo yekupfuura capacitor inofanirwa kupfuura nepakati pemaburi maviri kuti ibatanidze iyo yekudyara dura kune iyo fomati, nokudaro ichipeta kupaza kwehutachiona kweiyo gomba.

Tatu, nzira yekushandisa gomba

Kubudikidza neongororo iri pamusoro yezvipembenene zvemakomba-emaburi, tinogona kuona kuti mune yakakwira-kumhanya pcb dhizaini, izvo zvinoita sezviri nyore kuburikidza-maburi zvinowanzounza zvakakomba zvakashata kune dhizaini dhizaini. Kuti tideredze mhedzisiro yakaipa yeparasitic mhedzisiro yegomba, tinogona kuedza kuita zvinotevera mukugadzira:

1. Tichifunga nezvemutengo uye mhando yemasaini, inokwana saizi gomba inosarudzwa. Kana zvichidikanwa, funga kushandisa saizi dzakasiyana dzemakomba. Semuenzaniso, yesimba kana tambo dzepasi, funga kushandisa hukuru hukuru kudzikisira impedance, uye kune wiring yemasaini, shandisa maburi madiki. Ehe, sezvo gomba saizi inoderera, mutengo unoenderana uchawedzera.

2. Iwo maviri mafomula akurukurwa pamusoro anoratidza kuti kushandiswa kweakatetepa mabhodhi ePCB kunobatsira kudzikisa maviri eparasitic paramita ye perforations.

3. Iyo wiring yechiratidzo pabhodhi rePCBB haifanire kuchinja maturu kusvika pese pazvinogona, ndiko kuti, usashandise maburi asina basa zvakanyanya sezvinobvira.

4. Pini dzemagetsi uye nevhu rinofanira kucherwa mugomba riri padyo, uye tungamira pakati pegomba nembambo dzinofanira kuva pfupi sezvazvinogona. Akawanda kuburikidza-maburi anogona kutariswa zvakafanana kuti aderedze yakaenzana inductance.

5. Mamwe maburi epasi anoiswa padhuze nemakomba ekuratidzira chiratidzo kuti ape chiuno chiri padhuze chechiratidzo. Iwe unogona kunyange kuisa yakawanda yakawanda yekuwedzera maburi epasi paPCB. Ehe, iwe unofanirwa kuve unochinjika mukugadzira kwako. Iyo yemukati-yegomba modhi inokurukurwa pamusoro ndeye mamiriro ezvinhu apo pane mapadhi mune yega yega. Dzimwe nguva, tinogona kudzikisa kana kubvisa pads mune mamwe matete. Kunyanya muchiitiko chegomba rehupamhi rakakura kwazvo, zvinogona kutungamira mukuumbwa kwenzvimbo yakatemwa yedunhu mumutsara wemhangura, kugadzirisa dambudziko rakadaro mukuwedzera pakufambisa nzvimbo yegomba, tinogona zvakare kufunga gomba mumutsara wemhangura kudzikisa saizi yepad.

6. Kune yakakwirira-yekumhanyisa PCB mabhodhi ane yakakwira density, madiki maburi anogona kutariswa.