Kudzera mu bowo (VIA) ndi gawo lofunikira la Mipikisano PCB, ndipo mtengo wamabowo obowola nthawi zambiri umakhala wa 30% mpaka 40% yamtengo wopangira board ya PCB. Mwachidule, dzenje lililonse pa PCB lingatchulidwe kuti liwiro. Potengera magwiridwe antchito, bowo litha kugawidwa m’magulu awiri: limodzi limagwiritsidwa ntchito polumikizira magetsi pakati pa zigawo; Wina amagwiritsidwa ntchito pokonza kapena kuyika zida.

Potengera ndondomekoyi, mabowo obowolokawa amagawika m’magulu atatu, omwe ndi akhungu kudzera, oyikidwa m’manda kudzera kudzera. Mabowo akhungu ali pamwamba ndi pansi pa bolodi la PRINTED dera lanu ndipo mumakhala ndi kuya kwakukulumikizira dera loyandikana ndi dera lamkati pansipa. Kuzama kwa mabowo nthawi zambiri sikudutsa gawo lina (kabowo). Mabowo omwe adakwiriridwa ndi mabowo olumikizirana mkatikati mwa bolodi losindikizidwa lomwe silifikira pamwamba pa bolodi loyenda. The two types of holes are located in the inner layer of the circuit board, which is completed by the through-hole molding process before lamination, and several inner layers may be overlapped during the formation of the through-hole. Mtundu wachitatu, womwe umatchedwa mabowo, umadutsa pa bolodi lonselo ndipo ungagwiritsidwe ntchito kulumikizana kwamkati kapena kukweza ndikupeza mabowo azinthu zina. Because the through hole is easier to implement in the process, the cost is lower, so most printed circuit boards are used it, rather than the other two kinds of through hole. Otsatira kudzera m’mabowo, popanda kufotokozera mwapadera, adzawerengedwa ngati kudzera m’mabowo.

Kodi mumadziwa zochuluka bwanji za mapangidwe a PCB

Kuchokera pamapangidwe, dzenje lodzaza limapangidwa ndi magawo awiri, limodzi ndi dzenje lobowolera pakati ndipo linalo ndi malo oyandikira pobowola, monga zikuwonetsedwa pachithunzipa. Kukula kwa magawo awiriwa kumatsimikizira kukula kwa dzenje. Zachidziwikire, pakupanga kwa liwiro lalikulu, kachulukidwe ka PCB, wopanga nthawi zonse amafuna kuti dzenje likhale laling’ono momwe zingathere, chitsanzochi chimatha kusiya malo owongolera, kuwonjezera pamenepo, dzenje laling’ono, mphamvu yake ya parasitic ndiyocheperako, zambiri oyenera dera othamanga kwambiri. Koma kukula kwa dzenje kumachepa nthawi yomweyo kumabweretsa kukwera mtengo, ndipo kukula kwa dzenje sikungachepe popanda malire, kumangolekezera pobowola (kubowola) ndi kuyika (plating) ndi ukadaulo wina: zing’onozing’ono dzenje, Kutenga nthawi yayitali kumatenga nthawi, kumakhala kosavuta kuchoka pakati; Pamene kuya kwa dzenje kumakhala kopitilira kasanu ndi kawiri kupingasa kwa dzenje, ndikosatheka kutsimikizira mayikidwe amkuwa a khoma loboola. Mwachitsanzo, makulidwe amakono (kudzera kubowola) kwa bolodi la PCB la 6 ndi pafupifupi 50Mil, kotero kukula kocheperako komwe opanga a PCB amatha kupereka kumangofika 8Mil. The capacitance parasitic wa dzenje palokha pansi, ngati awiri a dzenje kudzipatula ndi D2, m’mimba mwake wa PAD dzenje ndi D1, makulidwe a bolodi PCB ndi T, ndi dielectric zonse za gawo lapansi ndi ε, mphamvu ya parasitic ya dzenje ili pafupifupi: C = 1.41εTD1 / (D2-D1)

The main effect of parasitic capacitance on the circuit is to prolong the signal rise time and reduce the circuit speed. Mwachitsanzo, bolodi PCB ndi makulidwe a 50Mil, ngati awiri mkati mwa dzenje ndi 10Mil, ndi awiri a PAD ndi 20Mil, ndi mtunda pakati pa PAD ndi pansi mkuwa ndi 32Mil, tikhoza kuyerekezera capacitance parasitic wa dzenje pogwiritsa ntchito fomuyi pamwambapa: C = 1.41 × 4.4 × 0.050 × 0.020 / (0.032-0.020) = 0.517pF, kuchuluka kwakanthawi komwe kumachitika ndi gawo ili la capacitance ndi: T10-90 = 2.2C (Z0 / 2) = 2.2 × 0.517x (55 / 2) = 31.28ps. Kuchokera pamitunduyi, zikuwonekeratu kuti ngakhale mphamvu ya parasitic capacitance kuchokera pa dzenje limodzi pakuchedwa kuchepa sikuwonekera, opanga ayenera kusamala ngati mabowo angapo amagwiritsidwa ntchito posinthira mosanjikiza.

Popanga ma circuits othamanga kwambiri a digito, kulowetsedwa kwa parasitic pakulowerera kwa dzenje nthawi zambiri kumakhala kwakukulu kuposa mphamvu ya parasitic capacitance. Makina ake amtundu wa parasitic adzafooketsa kuperekera kwa capacitance ndikuchepetsa kusefa kwa mphamvu yonse. Titha kungowerengera kufalikira kwa tiziromboti timene timayambira pozungulira pogwiritsa ntchito njira zotsatirazi: L = 5.08h [ln (4h / d) +1] pomwe L amatanthawuza kulowerera kwa dzenje, h ndiye kutalika kwa dzenje, ndi D ndikutalika kwa dzenje lapakati. Zitha kuwonedwa kuchokera ku equation kuti kukula kwa dzenje kumakhudza pang’ono pakulowerera, pomwe kutalika kwa dzenje kumakhudza kwambiri kutulutsa. Pogwiritsabe ntchito chitsanzo pamwambapa, kutuluka kunja kwa dzenje kumatha kuwerengedwa ngati L = 5.08 × 0.050 [ln (4 × 0.050 / 0.010) +1] = 1.015nh. Ngati nthawi yakukwera kwa chizindikirocho ndi 1ns, ndiye kuti kukula kwa impedance kofanana ndi: XL = πL / T10-90 = 3.19 ω. Kutayika kumeneku sikunganyalanyazidwe pakadali pano pafupipafupi. Makamaka, the capacitor yodutsa imayenera kudutsa m’mabowo awiri kuti agwirizane ndi kapangidwe kazomwe amapangidwazo, motero kuwirikiza kawiri kubowoleza kwa tiziromboti.

Kupyolera mu kusanthula pamwambapa kwa ziwalo za parasitic za dzenje, titha kuwona kuti mu kapangidwe ka PCB yothamanga kwambiri, dzenje lomwe limawoneka ngati losavuta nthawi zambiri limabweretsa zovuta zoyipa pakupanga dera. Pofuna kuchepetsa mavuto obwera chifukwa cha parasitic zotsatira za dzenje, titha kuchita zambiri momwe tingapangire kapangidwe kake: 1. Kuchokera pazinthu ziwiri za mtengo ndi mtundu wazizindikiro, sankhani kukula kwa dzenje. Mwachitsanzo, pamitundu 6-10 ya MEMORY module PCB design, ndibwino kuti musankhe 10 / 20mil (kuboola / pad) kudzera pabowo, paza bolodi yaying’ono kwambiri, mutha kuyesanso kugwiritsa ntchito 8 / 18mil kudzera dzenje. Ndiukadaulo wapano, zingakhale zovuta kugwiritsa ntchito mabowo ang’onoang’ono. Pogwiritsa ntchito magetsi kapena waya wapansi kudzera m’mabowo amatha kuganiziridwa kuti agwiritse ntchito kukula kwakukulu kuti muchepetse mphepo.

2. Njira ziwiri zomwe takambirana pamwambapa zikuwonetsa kuti kugwiritsa ntchito matabwa a PCB ochepera kumathandiza kuchepetsa magawo awiri a tiziromboti kudzera m’mabowo.

3. zingwe zamagetsi pa bolodi la PCB siziyenera kusintha zosanjikiza momwe zingathere, kutanthauza kuti, yesetsani kugwiritsa ntchito mabowo osafunikira.

4. Zikhomo zamagetsi ndi nthaka ziyenera kubooleredwa pafupi. Kufupikitsa kutsogolera pakati pa zikhomo ndi mabowo, kumakhala bwino, chifukwa kumabweretsa kuwonjezeka kwa kutayika. Nthawi yomweyo, mphamvu ndi ziwonetsero zapansi ziyenera kukhala zokulirapo momwe zingathere kuti muchepetse kuthamanga.

5. Ikani mabowo pafupi ndi mabowo osinthira ma siginolo kuti mupereke chingwe cholowera chapafupi ndi chizindikirocho. Mutha kuyika mabowo enanso ambiri pa PCB. Zachidziwikire, muyenera kukhala osinthasintha kapangidwe kanu. Mtundu wa dzenje lomwe tafotokozali pamwambapa ndi momwe mumakhalira mapepala aliyense wosanjikiza. Nthawi zina, titha kuchepetsa kapena kuchotsa ma pads m’malo ena. Makamaka pakakhala kuchuluka kwa dzenje ndilokulirapo, zimatha kupangitsa kuti pakhale poyambira podula mzere wamkuwa, kuti athetse vutoli kuphatikiza pakusuntha kwa dzenje, titha kuganiziranso za dzenje muzitsulo zamkuwa kuti muchepetse kukula kwa pad.