Ma jumper capacitor kapena decoupling capacitors amatha kuthetsa mavuto ena, koma zovuta zonse za ma capacitor, vias, pads, ndi mawaya ziyenera kuganiziridwa.

Nkhaniyi ifotokoza za EMC PCB kupanga umisiri kuchokera mbali zitatu: PCB wosanjikiza njira, luso masanjidwe ndi malamulo mawaya.

PCB layering strategy

Makulidwe, kudzera munjira ndi kuchuluka kwa zigawo mu kapangidwe ka bolodi lozungulira sizothandiza kuthetsa vutoli.Good layered stacking ndikuwonetsetsa kuti mabasi amagetsi azidutsa ndikudumphira ndikuchepetsa mphamvu yocheperako pagawo lamagetsi kapena pansi.Chinsinsi chotchinjiriza gawo la electromagnetic la chizindikiro ndi magetsi.

Kuchokera pakuwona kalozera wazizindikiro, njira yabwino yosanjirira iyenera kukhala yoyika zizindikiro zonse pagawo limodzi kapena zingapo, ndipo zigawozi zili pafupi ndi gawo la mphamvu kapena pansi.Kwa magetsi, njira yabwino yopangira magetsi iyenera kukhala kuti mphamvu yowonjezera ili pafupi ndi nthaka, ndipo mtunda wapakati pa mphamvu ya mphamvu ndi nthaka ndi yochepa kwambiri.Izi ndi zomwe tikukamba za njira ya "layer".Pansipa tidzakambirana za njira yabwino yosanjirira PCB.

1. Ndege yowonetsera ya chingwe cha waya iyenera kukhala m'dera la ndege yowonongeka.Ngati mawaya wosanjikiza sali m'malo owonetsera ndege ya reflow, padzakhala mizere yolumikizira kunja kwa malo owonetsera panthawi ya waya, zomwe zingayambitse mavuto a "radiation m'mphepete", ndikuwonjezeranso malo ozungulira chizindikiro, zomwe zimabweretsa mavuto. kuchuluka ma radiation mode osiyanasiyana.

2. Yesetsani kupewa kukhazikitsa zigawo zoyandikana nazo.Chifukwa mawonekedwe a mawaya ofananira pamagawo oyandikana nawo amatha kuyambitsa kuphatikizika kwa mawaya, ngati zigawo zoyandikana nazo sizingapewedwe, kusiyana pakati pa zigawo ziwiri za mawaya kuyenera kuchulukitsidwa moyenerera, ndipo kusanjikizana pakati pa waya wosanjikiza ndi mayendedwe ake azizindikiro kuyenera kuchepetsedwa.

3. Zigawo zoyandikana za ndege zipewe kupindika kwa ndege zolozera.Chifukwa pamene zolozera zikudutsana, kulumikiza mphamvu pakati pa zigawo kumapangitsa phokoso pakati pa zigawo kuti zigwirizane wina ndi mzake.

Multilayer board design

Mafupipafupi a wotchi akadutsa 5MHz, kapena nthawi yowuka siginecha imakhala yochepera 5ns, kuti muwongolere bwino malo ozungulira mawotchi, kapangidwe ka bolodi lamitundu ingapo nthawi zambiri kumafunika.Mfundo zotsatirazi ziyenera kutsatiridwa popanga ma multilayer board:

1. Chingwe cholumikizira mafungulo (wosanjikiza pomwe mzere wa wotchi, basi, mzere wamawonekedwe a mawonekedwe, mzere wa ma radio frequency, sinthaninso mzere wa siginecha, mzere wosankha wa chip ndi mizere yosiyanasiyana yowongolera ilipo) ziyenera kukhala moyandikana ndi ndege yonse yapansi, makamaka. pakati pa ndege ziwiri zapansi, Monga momwe chithunzi 1 chikusonyezera.

Mizere yofunikira nthawi zambiri imakhala ma radiation amphamvu kapena mizere yazizindikiro yovuta kwambiri.Mawaya omwe ali pafupi ndi ndege yapansi amatha kuchepetsa malo ozungulira chizindikiro, kuchepetsa mphamvu ya radiation kapena kupititsa patsogolo luso lodana ndi kusokoneza.

2. Ndege yamagetsi iyenera kubwezeredwa kufupi ndi ndege yapansi yomwe ili pafupi (mtengo wovomerezeka 5H～20H).Kubweza kwa ndege yamagetsi yokhudzana ndi ndege yobwerera kutha kuletsa vuto la "radiation ya m'mphepete", monga momwe chithunzi 2 chikusonyezera.

Kuonjezera apo, ndege yaikulu yogwiritsira ntchito mphamvu ya bolodi (ndege yomwe imagwiritsidwa ntchito kwambiri) iyenera kukhala pafupi ndi ndege yake yapansi kuti ichepetse bwino malo ozungulira magetsi, monga momwe tawonetsera pa Chithunzi 3.

3. Kaya palibe mzere wa chizindikiro ≥50MHz pa TOP ndi BOTTOM wosanjikiza wa bolodi.Ngati ndi choncho, ndi bwino kuyenda chizindikiro chapamwamba kwambiri pakati pa zigawo ziwiri za ndege kuti zitseke ma radiation ake kumlengalenga.

Bolodi yokhala ndi gulu limodzi ndi kapangidwe ka bolodi la magawo awiri

Pakupanga matabwa amtundu umodzi ndi matabwa awiri, mapangidwe a mizere yofunikira ndi mizere yamagetsi ayenera kuperekedwa.Payenera kukhala chingwe chapansi pafupi ndi chofananira ndi njira yamagetsi kuti muchepetse gawo la lupu yamagetsi.

"Guide Ground Line" iyenera kuikidwa kumbali zonse ziwiri za mzere wofunikira wa bolodi limodzi lokha, monga momwe tawonetsera pa Chithunzi 4. Mzere wofunikira wa bolodi wamagulu awiri uyenera kukhala ndi malo akuluakulu pa ndege yowonetsera. , kapena njira yofanana ndi bolodi limodzi lokha, kupanga "Guide Ground Line", monga momwe tawonetsera pa Chithunzi 5. "Waya wapansi wa alonda" kumbali zonse za mzere wofunikira ukhoza kuchepetsa malo ozungulira chizindikiro kumbali imodzi, komanso kupewa crosstalk pakati pa mzere wa siginecha ndi mizere ina yolumikizira.

Maluso a mapangidwe a PCB

Popanga mapangidwe a PCB, muyenera kuyang'anitsitsa ndondomeko ya mapangidwe oyika mzere wowongoka motsatira njira yoyendetsera chizindikiro, ndipo yesetsani kupewa kuyendayenda mmbuyo ndi mtsogolo, monga momwe tawonetsera pa Chithunzi 6. Izi zikhoza kupeŵa kugwirizanitsa kwachindunji ndi kukhudza khalidwe la chizindikiro. .

Kuphatikiza apo, pofuna kupewa kusokonezana komanso kulumikizana pakati pa mabwalo ndi zida zamagetsi, kuyika kwa mabwalo ndi masanjidwe a zigawo ziyenera kutsatira mfundo izi:

1. Ngati mawonekedwe a "nthaka yoyera" apangidwa pa bolodi, zosefera ndi zigawo zodzipatula ziyenera kuikidwa pa gulu lodzipatula pakati pa "nthaka yoyera" ndi malo ogwira ntchito.Izi zitha kulepheretsa zida zosefera kapena zodzipatula kuti zisalumikizane wina ndi mnzake kudzera mugawo la planar, zomwe zimafooketsa zotsatira zake.Kuphatikiza apo, pa "nthaka yoyera", kupatula zida zosefera ndi chitetezo, palibe zida zina zomwe zingayikidwe.

2. Pamene ma modules angapo amaikidwa pa PCB yomweyo, maulendo a digito ndi maulendo a analogi, maulendo othamanga kwambiri ndi otsika ayenera kuikidwa mosiyana kuti apewe kusokonezana pakati pa maulendo a digito, maulendo a analogi, maulendo othamanga kwambiri, ndi otsika. - mabwalo othamanga.Kuonjezera apo, pamene maulendo apamwamba, apakati, ndi otsika kwambiri amakhalapo pa bolodi la dera panthawi imodzimodziyo, pofuna kupewa phokoso lamtundu wamtundu wamtunda kuti lisatuluke kudzera mu mawonekedwe, ndondomeko ya masanjidwe mu Chithunzi 7 iyenera kukhala .

3. Chigawo cha fyuluta cha doko lothandizira mphamvu la bolodi la dera liyenera kuyikidwa pafupi ndi mawonekedwe kuti asagwirizanenso ndi dera losefedwa.

4. Zigawo zosefera, zoteteza ndi zodzipatula za mawonekedwe ozungulira zimayikidwa pafupi ndi mawonekedwe, monga momwe tawonetsera pa Chithunzi 9, chomwe chingathe kukwaniritsa zotsatira za chitetezo, kusefa ndi kudzipatula.Ngati pali zonse zosefera ndi zozungulira zoteteza pamawonekedwe, mfundo yachitetezo choyamba kenako kusefa iyenera kukhala .Chifukwa dera lodzitchinjiriza limagwiritsidwa ntchito pakuwonjezera kwakunja ndi kuponderezana mopitilira muyeso, ngati dera lodzitchinjiriza litayikidwa pambuyo pa fyuluta, dera la fyuluta lidzawonongeka chifukwa cha overvoltage ndi overcurrent.

Kuphatikiza apo, popeza mizere yolowera ndi kutulutsa kwa dera idzafooketsa kusefa, kudzipatula kapena chitetezo ikaphatikizidwa wina ndi mzake, onetsetsani kuti mizere yolowera ndi yotulutsa ya fyuluta (zosefera), kudzipatula ndi chitetezo sizimatero. amalumikizana wina ndi mzake panthawi yokonza.

5. Mabwalo okhudzidwa kapena zigawo zikuluzikulu (monga mabwalo obwezeretsanso, etc.) ayenera kukhala osachepera 1000 mils kutali ndi m'mphepete mwa bolodi, makamaka m'mphepete mwa mawonekedwe a bolodi.


6. Kusungirako mphamvu ndi ma capacitor a frequency frequency frequency ayenera kuikidwa pafupi ndi maulendo a unit kapena zipangizo zomwe zili ndi kusintha kwakukulu kwaposachedwa (monga zolowetsa ndi zotulutsa za module yamagetsi, mafani ndi ma relays) kuti achepetse malo ozungulira amakono akuluakulu. malupu.

7. Zigawo zosefera ziyenera kuyikidwa mbali ndi mbali kuti ziteteze dera losefedwa kuti lisasokonezedwenso.

8. Sungani zida zamphamvu zama radiation monga makhiristo, ma crystal oscillators, ma relay, kusinthana kwamagetsi, etc. kutali ndi cholumikizira cholumikizira bolodi osachepera 1000 mils.Mwanjira iyi, zosokonezazo zimatha kuwunikira mwachindunji kunja kapena zapano zimatha kuphatikizidwa ndi chingwe chotuluka kuti chiwolere kunja.

REALTER: Bungwe Losindikizidwa Lozungulira, PCB Design, PCB Assembly