Yekutanga Mitemo yePCB Dhizaini Yepamusoro-Unhu Circuit Boards

Dhizaini yePrinted Circuit Board ( PCB ) ipfungwa huru yekugadzirwa kwezvigadzirwa zvemagetsi zvemazuva ano, zvinoda kunzwisisa kwakanyatsojeka kweinjiniya yemagetsi, dzidziso yemagetsi, uye miganho yekugadzira. Sezvo zvigadzirwa zvemagetsi zvichiva zvakanyanyisa, kuoma kwedhizaini yePCB kwawedzera, zvichiita kuti kutevedzera mitemo chaiyo yekugadzira uye maitiro akanakisa kuve kwakakosha. Mitemo iyi inovimbisa kushanda, kugona kugadzirwa, kuvimbika, uye kushanda zvakanaka kwemari. PCB yakagadzirwa zvakanaka inowanzo tsanangura kubudirira kwechigadzirwa maererano nekushanda uye kugara kwenguva refu. Chinyorwa chino chinopa kuongororwa kwakadzama kwemitemo yakakosha yekugadzira PCB, ichisimbisa mativi ehunyanzvi uye kufunga nezvehunyanzvi.

1. Layer Stack-Up Mitemo

Layer stack-up inoreva kurongeka uye kurongeka kweiyo conductive layer, insulating layer, uye substrates mukati mePCB. Kuronga kwakaringana kwakakosha pakutendeseka kwechiratidzo, electromagnetic interference (EMI) control, uye impedance yekufananidza.

• Kugadzikana kweSymmetrical Layer Stack-Up : Kuti michina igadzikane uye kudzivirira kutsveyama panguva yekupisa, chengetedza kugadzikana kwakaenzana kwakatenderedza pakati pePCB. Kugadzikana kwakaenzana kunoderedza kushushikana kwemashini, kunyanya mumabhodhi ane layer akawanda.

• Mapurani Ekutarisa : Mapurani ekuratidza anofanira kunge ari pedyo nepurani dzekutarisa dzinoenderera mberi (pasi kana pasi). Izvi zvinoderedza EMI nekupa nzira yekudzoka isina kupindira zvakanyanya, iyo inokosha kune mapurani ekukurumidza.

• Kusarudzwa kweZvinhu zveDielectric : Kusachinja-chinja kwe dielectric (Dk) uye tangent yekurasikirwa (Df) yezvikamu zvinodzivirira kupararira kwechiratidzo zvinokanganisa kumhanya kwekuparadzira chiratidzo uye kudzikira kwesimba. Mashandisirwo e-frequency anowanzoda zvinhu zvinoderedza kurasikirwa senge specialty low-loss laminate kana Megtron pane standard FR-4 kuderedza kuora kwechiratidzo.

• Kudzora Kudzivirira Kwemagetsi : Mitsetse yekutumira inofanirwa kugadzirwa kuti ichengetedze kupindirana kwemagetsi, kazhinji pakati pe50 kusvika 75 ohms yezviratidzo zvine magumo ega kana 90 kusvika 100 ohms yezvikamu zvakasiyana. Kupindirana kwemagetsi kunoenderana nehupamhi hwetrace, nzvimbo, uye hunhu hwe dielectric. Zvigadziriso zvemagetsi, zvakaita seAnsys HFSS kana CST Studio, zvinogona kubatsira mukutevedzera nemazvo zvinodiwa zvekudzivirira.

2. Component Placement Mitemo

Kuiswa kwechikamu kunoraira kwete chete kuita kwePCB asiwo kugadzira kwayo uye kudziya kwekutonga.

• Inoshanda Block Organisation: Isa zvikamu mumabhuroko anonzwisisika zvichienderana nebasa rawo, kuenderana nekuyerera kwechiratidzo. Semuenzaniso, high-speed components (processors, memory) inofanira kuiswa nechepakati, iine zvinhu zvinotsigira (decoupling capacitors, magetsi regulators) zvakavapoteredza kuderedza kureba kwenzira yechiratidzo.
• Thermal Management Kufunga: Zvikamu zvine simba repamusoro zvakaita seMOSFETs, mavoltage regulators, uye ma processors anofanirwa kuparadzaniswa zvakaringana kufambisa kupisa. Shandisa thermal vias pasi zvinoriumba izvi kutamisa kupisa kubva chikamu Pedhi kuti mukati kana zvokunze kupisa singi akaturikidzana.
• Decoupling Capacitor Placement: Bypass uye decoupling capacitors inofanira kuiswa mukati me 0.1 inches (2.5 mm) yeIC simba pini. Izvi zvinodzikisira iyo loop nzvimbo, kuderedza yakakwirira-frequency ruzha nekunyatso bvisa kuchinjika kwemagetsi emagetsi.
• Clearances uye Creepage Distances: Kune yakakwirira-voltage dhizaini, ita shuwa creepage yakakodzera uye kureba kureba pakati pezvikamu kudzivirira arcing kana dielectric kuparara. IPC-2221 zviyero zvinokurudzira kubvumidzwa kwakanangana nekushanda kwemagetsi uye zvakatipoteredza.

3. Trace Routing Mitemo

Routing traces ndechimwe chezvakanyanya kuomesesa zvikamu zvePCB dhizaini, kunyanya mumaseketi ekumhanya uye akakwira-frequency.

• Madhairekitori eImpedance Anodzorwa : Madhairekitori eImpedance anodzorwa akakosha pakuvimbika kwechiratidzo, kunyanya mumagadzirirwo ekumhanya kukuru. Upamhi hwemadhairekitori, nzvimbo, uye daro remareferensi zvinofanirwa kuverengerwa nokungwarira kuti zvisangane nezvinodiwa zveimpedance. Zvishandiso zvakaita seIPC-2141 zvinogona kubatsira pakuverenga upamhi hwemadhairekitori hwakakodzera zvichibva pane hunhu hwezvinhu.

• Kuronga Mapairi Akasiyana : Mapairi akasiyana anofanira kuchengetedza urefu hwakaenzana hwetrace uye nzvimbo dzakafanana kuchengetedza differential impedance, yakakosha paUSB, HDMI, uye Ethernet protocols. Kusawirirana kwehurefu mumapairi akasiyana kunofanira kuchengetwa pasi pe5 mils kudzivirira nguva yekutsveyama.

• Kuburikidza neKushandiswa muZviratidzo Zvinomhanya Nekukurumidza : Zviratidzo zvakawandisa zvinogona kukonzera kusagadzikana kweimpedance, zvichiwedzera simba reparasitic uye inductance. Kune zviratidzo zvinonzwa, funga nezvekuderedza kuburikidza nekuchinja kana kushandisa zviratidzo zvakaboorwa kumashure, izvo zvinoderedza kuburikidza nehurefu hwestub, zvichideredza kuratidzwa kwechiratidzo uye kurasikirwa.

• Kuderedza Kureba kweStub : Stubs, kana kuti traces dzisina kuvharwa, dzinoshanda seantennas dzinogona kukonzera kuratidzwa kwechiratidzo. Mumagadzirirwo eRF, kuratidzwa kwetraces dzisina stubs uye kushandisa ma blind kana kuti vias akavigwa kunobatsira kuderedza kuratidzwa.

• Upamhi hweTrace yeKukwanisa Kutakura Current : Shandisa zviyero zveIPC-2152 kuti uone upamhi hwetrace zvichibva pane zvinodiwa nekutakura current. Kune ma layers emukati, gwara rinowanzo shandiswa i10 mils pa ampere, nepo ma layers ekunze achida anenge 15 mils pa ampere kudzivirira kukwira kwakanyanya kwekushisa.

Pakuronga kugadzirwa, zvinobatsirawo kuenzanisa nyaya iyi neongororo yekugadzira PCB uye kugona kugadzira PCB usati wapedzisa kugadzira kana kugadzira pasuru.

4. Dhizaini yeKugadzira (DFM) Mitemo

DFM inova nechokwadi chekuti PCB dhizaini inogona kugadzirwa zvine mutengo pasina zvikanganiso.

• Magadzirirwo eAnnular Ring : Ring yeannular (nzvimbo inofambisa mhepo yakatenderedza maburi) inofanira kunge yakakura zvakakwana kuti ikwanise kutakura misligration inogona kuitika. Kune maburi akaiswa plated-through, IPC inokurudzira kuti ring yeannular ive ne10 mils, kunyangwe magadzirirwo emhando yepamusoro anogona kubvumira maring madiki kana kugona kwekugadzira kuchitsigira.

• Nhungamiro dzeMasiki yeSolder neMasiki yePaste : Kubvisa mask yesolder zvakakodzera kwakakosha kudzivirira kusangana kwemasolder. Kukura kwemasiki kunokurudzirwa (musiyano uripo pakati pepad nemasiki yesolder) i2-4 mils, zvichienderana nekushivirira kwekugadzira uye maitiro ekugadzira.

• Saizi dzeComponent Pad uye Via-in-Pad : Mapedhi anofanira kunge akaenzana nehukuru hwecomponent lead, kazhinji aine dhayamita yekuwedzera ye0.1 kusvika 0.2 mm yemaburi akaiswa plated-through. Kana ukashandisa via-in-pad, iva nechokwadi chekuti azere uye akavharwa kudzivirira solder wicking, izvo zvinogona kukonzera kusasimba kwemajoini e solder.

• Kubviswa kwemhangura kubva pamucheto kusvika pamucheto : Kuti pasave nekupatsanurwa uye kudzivirira kupfupika kwemhangura panguva yekubvisa mapaneru, zvinhu zvemhangura zvinofanirwa kudzoserwa kumashure kubva pamucheto webhodhi neinenge 0.5 mm.

5. Signal Integrity (SI) uye Crosstalk Reduction Mitemo

Signal kutendeseka (SI) yakakosha kune yakakwirira-kumhanya dhizaini, uko masaini edhijitari anoda kushandura zvakachena pasina kukanganisa.

• Kudzivirira Kutevera Kwekona Yerudyi : Kukombama kwekona yerudyi kunogona kukonzera kuratidzwa kwechiratidzo uye matambudziko eEMI. Kune zviratidzo zvakakosha, shandisa kukombama kwemadhigirii makumi mana nemashanu kana, zvakanaka, kombama matraces kuti uchengetedze impedance yakafanana.

• Nzira Dzekudzoka Pasi : Zviratidzo zvinofanirwa kunge zvine nzira yekudzoka pasi inoramba ichienderera mberi kuderedza kutenderera kweropa uye EMI. Iva nechokwadi chekuti zviratidzo zviri pedyo nenzvimbo dzepasi, zviri nani kuti zvive pedyo nenzvimbo dziri mudura.

• Kuparadzanisa Nzvimbo Dzekuderedza Kutaurirana : Chengetedza nzvimbo ine upamhi hwekanenge katatu kupfuura trace width pakati pe high-speed traces kuti uderedze capacitive ne inductive coupling, izvo zvinogona kukonzera crosstalk.

• Kuderedza uye Kugumisa Stub : MuRF uye madhizaini edhijitari anomhanya zvakanyanya, dzivisa mastub nekutumira masaini nemagumo akakodzera. Kana zvisingadzivisike, mastub anofanira kunge ari mapfupi sezvinobvira kuderedza kuratidzwa.

6. Simba Kutendeseka (PI) Mitemo

Kuchengetedza kugadzikana kwemagetsi kwakakosha kune dhijitari uye analog maseketi, kunyanya nekuwedzera kwemagetsi density mumaPCB emazuva ano.

• Mapurani Emagetsi Nepasi : Mapurani emagetsi akasimba nepasi anopa nzira yekudzora kupindira kwemagetsi zvishoma, zvichideredza kudonha kwemagetsi uye ruzha. Mapurani aya anoshandawo semuchina wekuparadzira kupisa, zvichivandudza manejimendi yekupisa.

• Kugadzira Network yeDecoupling : Shandisa musanganiswa wemacapacitor ekuwedzera neakakwira-frequency ari pedyo neIC yega yega. Macapacitor ekuwedzera (10 μF kana kupfuura) anopa simba panguva dzezviitiko zvenguva pfupi, nepo macapacitor ekuwedzera-frequency (0.01–0.1 μF) anoderedza ruzha rwekuwedzera-frequency.

• Kuderedza Nzvimbo Yekutenderera Kwemagetsi : Kuchengetedza simba nematombo ari pasi pevhu zviri pedyo kunoderedza nzvimbo yekutenderera, izvo zvinoderedzawo EMI ine radiation. Mabhodhi akawanda anobatsirwa nekuisa magetsi nematombo ari pasi pevhu ari pedyo.

• Kuenzanisa Simba Rinokwana : Kuenzanisa simba rinokwana (semuenzaniso, kushandisa software yakaita seAnsys SIwave) kunogona kufanotaura kuyerera kwemagetsi uye kuona nzvimbo dzinopisa, zvichibatsira kugadzirisa nzvimbo dzakapatsanurwa uye dhizaini yepuraneti.

7. Thermal Management Mitemo

Sezvo zvishandiso zvinoshandisa simba rakawanda, kutonga kwekushisa kunowedzera kukosha kudzivirira kupisa uye kuve nechokwadi chekushanda kwakavimbika.

• Kupisa Kuburikidza neMagadzirirwo Emagetsi : Zvikamu zvine simba guru, zvakaita seFPGAs, zvinofanirwa kunge zvine magadzirirwo emagetsi anodziya kuti zvitamise kupisa kubva kumapedhi emagetsi kuenda kumahedhi emukati kana ekunze. Mahedhi anowanzo zadzwa ne epoxy kana kuti akavharirwa kuti ave nechokwadi chekuti zvinosungirirwa zvakanaka.

• Madhizaini ekupisa nemidziyo yekupisa : Mumagadzirirwo ane simba guru, batanidzai madhizaini ekupisa kana michina yekupisa kuzvinhu zvinopfuura mwero wekupisa wakachengeteka. Mamwe maPCB angada mapaipi ekupisa akaiswa mukati kana substrates dzesimbi kuti dzitonhore zvakanaka.

• Kutenderera Kwemhepo Nekumanikidzwa Kwemhepo : Ronga zvinhu kuti ukurudzire kutenderera kwemhepo kwechisikigo kana kugadzirisa kumanikidzwa kwemhepo munzvimbo dzine simba guru. Kune magadzirirwo emagetsi ane huwandu hwakawanda, isa zvinhu zvinonzwa kupisa kure nezvinodziya.

8. Kuedza uye Kuongorora Mitemo

Kuedza uye kuongorora kunobatsira kuona kushanda kwePCB uye mhando isati yazara kugadzirwa.

• Kusvikika Kwenzvimbo Dzekuyedza : Wedzera nzvimbo dzekuyedza dzema "critical nodes" kuti zviite nyore kuyedza mukati medunhu (ICT) uye kugadzirisa matambudziko. Iva nechokwadi chekuti nzvimbo dzekuyedza dzakaiswa kumativi anowanikwa uye dzinoenderana ne "test probes".

• Zvinodiwa pakuongorora AOI neX-Ray : Otomatiki Optical Inspection (AOI) inoona zvikanganiso pakuiswa kwe solder nezvikamu, ukuwo X-ray ichikosha pamapuranga ane Ball Grid Array (BGA) package, uko majoini e solder akavharwa. Iva nechokwadi chekuti marongerwo acho anotevedzera gwara reAOI kuti vaonekwe zvakajeka.

• Kuskena Muganho neJTAG : Kune madhijitari, kuskena muganho (IEEE 1149.1 JTAG) kunopa nzira yekuedza kubatana pasina kupinda zvakananga muprobe. Batanidza mapoinzi ekuyedza eJTAG kuti zvive nyore kuyedza, kunyanya mumabhodhi akakora kana akawanda.

mhedziso

Kutevera iyi mitemo yakakosha muPCB dhizaini yakakosha pakugadzira emhando yepamusoro, yakavimbika, uye inogadzirwa akadhindwa edunhu mabhodhi. Nekuwedzera kwakaoma dhizaini, nhungamiro inopiwa pano inovimbisa kuti chikamu chega chega-kubva pakaturikidzana kusvika pakuyedzwa-chinosangana nezviyero zveindasitiri.

Nekuomerera kune idzi misimboti, vagadziri vanogona kuderedza zvikanganiso, kuderedza mitengo yekugadzira, uye kuwedzera mashandiro uye kusimba kwePCB dzavo.

Kuti uwane chiitiko chisina musono, shanda nesu kune yakazara PCB mhinduro. Chikwata chedu chevagadziri vePCB vane hunyanzvi vanogona kukubatsira nekugadzira, kugadzira, uye kugadzira — zvese zviri pasi pedenga rimwe. Tisarudze isu kune zvaunoda zvemagetsi uye unakirwe neyakagadziridzwa, imwe-kumira sevhisi inopa yakasarudzika mhando uye kuvimbika!