Kuchokera ku dziko la PCB

1. Kodi mungaganizire bwanji zofananira popanga mapangidwe apamwamba kwambiri a PCB?

Mukapanga mabwalo othamanga kwambiri a PCB, kufananitsa kwa impedance ndi chimodzi mwazinthu zomwe zimapangidwira.Mtengo wa impedance uli ndi ubale weniweni ndi njira yolumikizira, monga kuyenda pamtunda (microstrip) kapena wosanjikiza wamkati (stripline/double stripline), mtunda kuchokera pagawo lolozera (mphamvu wosanjikiza kapena wosanjikiza pansi), m'lifupi mwa waya, zinthu za PCB. , ndi zina zotere. Zonse zidzakhudza mtengo wolepheretsa kutsata.

Ndiko kuti, mtengo wa impedance ukhoza kutsimikiziridwa pambuyo pa waya.Nthawi zambiri, pulogalamu yoyeserera siyingaganizire zina zomwe zimasiyanitsidwa ndi mawaya chifukwa cha kuchepa kwa mtundu wadera kapena masamu omwe amagwiritsidwa ntchito.Panthawiyi, zoletsa zina zokha (kuthetsa), monga kukana mndandanda, zikhoza kusungidwa pazithunzi za schematic.Chepetsani zotsatira za discontinuity mu trace impedance.Yankho lenileni la vutoli ndi kuyesa kupewa impedance discontinuities pamene mawaya.
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2. Pakakhala midadada yambiri ya digito / analogi mu bolodi la PCB, njira yodziwika bwino ndikulekanitsa malo a digito / analogi.Chifukwa chiyani?

Chifukwa cholekanitsa malo a digito / analogi ndi chifukwa chakuti dera la digito lidzapanga phokoso mu mphamvu ndi pansi pamene mukusintha pakati pa kuthekera kwakukulu ndi kochepa.Kukula kwa phokoso kumayenderana ndi liwiro la chizindikiro ndi kukula kwake.

Ngati ndege yapansi siinagawidwe ndipo phokoso lopangidwa ndi dera la digito ndi lalikulu ndipo maulendo a analoji ali pafupi kwambiri, ngakhale zizindikiro za digito-to-analoji sizidutsa, chizindikiro cha analogi chidzasokonezedwabe ndi nthaka. phokoso.Izi zikutanthauza kuti, njira yosagawanika ya digito-to-analog ingagwiritsidwe ntchito pamene dera la dera la analogi liri kutali ndi dera la digito lomwe limapanga phokoso lalikulu.

3. Pamapangidwe othamanga kwambiri a PCB, ndi mbali ziti zomwe wopanga ayenera kuganizira za malamulo a EMC ndi EMI?

Nthawi zambiri, mapangidwe a EMI/EMC amayenera kuganizira zowunikira komanso kuchitidwa nthawi imodzi.Yoyamba ndi ya gawo lapamwamba la pafupipafupi (> 30MHz) ndipo yomalizayo ndi gawo lotsika (<30MHz).Kotero inu simungakhoze basi kulabadira mkulu pafupipafupi ndi kunyalanyaza otsika pafupipafupi.

Mapangidwe abwino a EMI / EMC ayenera kuganizira malo a chipangizocho, makonzedwe a stack PCB, njira yolumikizira yofunika, kusankha kwa chipangizo, ndi zina zotero kumayambiriro kwa masanjidwewo.Ngati palibe makonzedwe abwinoko kale, adzathetsedwa pambuyo pake.Idzalandira kawiri zotsatira ndi theka la khama ndikuwonjezera mtengo.

Mwachitsanzo, malo a jenereta ya wotchi sayenera kukhala pafupi ndi cholumikizira chakunja momwe angathere.Zizindikiro zothamanga kwambiri ziyenera kupita kumalo amkati momwe zingathere.Samalani ndi mawonekedwe a impedance ndi kupitiliza kwa gawo lolozera kuti muchepetse zowunikira.Mlingo wakupha wa chizindikiro chokankhidwa ndi chipangizocho uyenera kukhala wocheperako kuti uchepetse kutalika.Zigawo zafupipafupi, posankha ma decoupling / bypass capacitors, samalani ngati kuyankha kwake pafupipafupi kumakwaniritsa zofunikira kuti muchepetse phokoso pa ndege yamagetsi.

Kuonjezera apo, tcherani khutu ku njira yobwereranso yamagetsi apamwamba kwambiri kuti apange malo ozungulira kukhala ang'onoang'ono momwe angathere (ndiko kuti, loop impedance kukhala yaying'ono momwe mungathere) kuchepetsa ma radiation.Pansi amathanso kugawidwa kuti aziwongolera kuchuluka kwa phokoso lambiri.Pomaliza, sankhani bwino malo a chassis pakati pa PCB ndi nyumba.
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4. Popanga bolodi la pcb, kuti muchepetse kusokoneza, kodi waya wapansi uyenera kupanga fomu yotsekedwa?

Popanga matabwa a PCB, malo ozungulira nthawi zambiri amachepetsedwa kuti achepetse kusokoneza.Poyika mzere wapansi, sayenera kuikidwa motsekedwa, koma ndi bwino kuukonza mu mawonekedwe a nthambi, ndipo dera la nthaka liyenera kuwonjezeka momwe mungathere.

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5. Kodi mungasinthire bwanji ma topology kuti muwongolere kukhulupirika kwa ma sign?

Mayendedwe amtundu wamtunduwu ndi ovuta kwambiri, chifukwa kwa ma unidirectional, ma bidirectional sign, ndi mitundu yosiyanasiyana yazizindikiro, zikoka za topology ndizosiyana, ndipo ndizovuta kunena kuti ndi topology iti yomwe imapindulitsa pamtundu wazizindikiro.Ndipo pochita kayeseleledwe kathu, komwe kugwiritsiridwa ntchito kwa topology kumakhala kovutirapo kwa mainjiniya, kumafunikira kumvetsetsa kwamayendedwe ozungulira, mitundu yazizindikiro, ngakhalenso kuvutitsidwa kwa waya.
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6. Momwe mungathanirane ndi masanjidwe ndi ma waya kuti mutsimikizire kukhazikika kwa ma siginecha pamwamba pa 100M?

Chinsinsi cha mawaya othamanga kwambiri a digito ndikuchepetsa kukhudzidwa kwa mizere yopatsira pamtundu wazizindikiro.Choncho, masanjidwe a zizindikiro zothamanga kwambiri pamwamba pa 100M amafuna kuti zizindikiro zikhale zazifupi momwe zingathere.M'mabwalo a digito, ma siginecha othamanga kwambiri amatanthauzidwa ndi nthawi yochedwa kukwera.

Kuphatikiza apo, mitundu yosiyanasiyana ya ma sign (monga TTL, GTL, LVTTL) ili ndi njira zosiyanasiyana zowonetsetsa kuti siginecha yabwino.