Buyini ububanzi bomugqa?

Ake siqale ngezisekelo. Buyini ngempela ububanzi bokulandela? Kungani kubalulekile ukucacisa ububanzi bethrekhi ethile? Inhloso ye PCB ukuhlanganisa izintambo ukuxhuma noma yiluphi uhlobo lwesiginali kagesi (i-analog, idijithali noma amandla) kusuka kunodi eyodwa kuya kwenye.

I-node ingaba yiphini yengxenye, igatsha lokulandela umkhondo noma indiza enkulu, noma iphedi elingenalutho noma iphuzu lokuhlola lokuphenya. Ububanzi bokulandela umkhondo kuvame ukukalwa ngama-mils noma izinkulungwane zamasentimitha. Ububanzi bezintambo ezijwayelekile zamasiginali ajwayelekile (azikho izidingo ezikhethekile) kungaba ngamasentimitha amaningana ubude ebangeni lama-7-12 mils, kepha izinto eziningi kufanele zicatshangelwe lapho kuchazwa ububanzi bezintambo nobude.

Uhlelo lokusebenza luvamise ukushayela ububanzi bezintambo nohlobo lwentambo ekwakhiweni kwe-PCB futhi, kwesinye isikhathi, kuvamise ukulinganisa izindleko zokukhiqiza ze-PCB, ukuminyana / usayizi webhodi, nokusebenza. Uma ibhodi linezidingo ezithile zokuklama, njengokusebenza kwejubane, umsindo noma ukucindezela ukuhlangana, noma amandla wamanje / i-voltage ephezulu, ububanzi nohlobo lokulandela umkhondo kungabaluleke ngaphezu kokuqhakambisa izindleko zokukhiqiza ze-PCB engenalutho noma usayizi webhodi jikelele.

Incazelo ephathelene nezintambo ekukhiqizeni i-PCB

Imvamisa, imininingwane elandelayo ehlobene nentambo iqala ukukhuphula izindleko zokukhiqiza i-PCBS engenalutho.

Ngenxa yokubekezelela okuqinile kwe-PCB nemishini ephezulu edingekayo ekukhiqizeni, ekuhloleni noma ekuhlolweni kwe-PCBS, izindleko ziba phezulu kakhulu:

L Trace ububanzi obungaphansi kuka-5 mil (0.005 in.)

L Trace isikhala ngaphansi kwamamitha ama-5

L Ngezimbobo ezingaphansi kuka-8 mil ububanzi

L Ukulandela ngobukhulu okungaphansi noma okulingana no-ounce owodwa (olingana no-1 mils)

L Amabili ahlukene nobude obulawulwayo noma impedance yezintambo

Imiklamo eminyene kakhulu ehlanganisa ukuthatha isikhala kwe-PCB, okufana ne-BGA ehlukaniswe kahle kakhulu noma amabhasi wokubala wesiginali ephezulu, kungadinga ububanzi bomugqa we-2.5 mil, kanye nezinhlobo ezikhethekile zemigodi enqamula ngobubanzi obufinyelela ku-6 mil, njengoba laser kubhola microthrough-izimbobo. Ngakolunye uhlangothi, eminye imiklamo yamandla aphezulu ingadinga izintambo ezinkulu kakhulu noma izindiza, kudle izingqimba zonke futhi kuthelwe ama-ounces ashubile kunokujwayelekile. Kuzicelo ezinomkhawulo wesikhala, kungadingeka amapuleti amancane kakhulu aqukethe izingqimba eziningana kanye nobukhulu obulinganiselwe bokuphonsa ithusi lobukhulu besigamu (0.7 mil ukujiya).

Kwezinye izimo, ukwakheka kokuxhumana kwejubane kusuka kolunye uhlangothi kuya kolunye kungadinga ukuxhunywa nge-impedance elawulwayo nobubanzi obuthile kanye nesikhala phakathi komunye nomunye ukunciphisa ukubumbana nokuhlangana kokungeniswa. Noma ukwakhiwa kungadinga ubude obuthile ukufanisa amanye amasiginali afanele ebhasini. Izicelo ezinamandla amakhulu zidinga izici ezithile zokuphepha, njengokunciphisa ibanga phakathi kwezimpawu ezimbili eziveziwe zokuhlukanisa ukuvimbela ukuhlangana. Akunandaba nezimpawu noma izici, ukulandelela izincazelo kubalulekile, ngakho-ke ake sihlole izinhlelo zokusebenza ezahlukahlukene.

Ububanzi obuhlukahlukene bezintambo nobukhulu

Ama-PCBS ngokuvamile aqukethe ububanzi obuhlukahlukene bomugqa, ngoba ancike kuzidingo zesiginali (bona Umfanekiso 1). Imikhondo emihle ekhonjisiwe yenzelwe amasiginali wezinga elijwayelekile le-TTL (transistor-transistor logic) futhi ayinazidingo ezikhethekile zokuvikelwa okuphezulu kwamanje noma komsindo.

Lezi kuzoba izinhlobo ezivame kakhulu zezintambo ebhodini.

Izintambo ezijiyile zenzelwe amandla okuphatha amanje futhi zingasetshenziselwa iziphambeko noma imisebenzi ehlobene namandla edinga amandla aphakeme, njengabalandeli, izinjini, nokudluliswa kwamandla okujwayelekile kuzingxenye ezisezingeni eliphansi. Ingxenye engaphezulu kwesobunxele yalesi sibalo ikhombisa nesiginali yokuhlukanisa (i-USB esheshayo) echaza isikhala nobubanzi obuthile ukuhlangabezana nezidingo ze-impedance ka-90 ω. Umdwebo 2 ukhombisa ibhodi lesifunda elijiyene kancane elinezendlalelo eziyisithupha futhi elidinga umhlangano we-BGA (ball grid array) odinga izintambo ezinhle.

Ungabala kanjani ububanzi bomugqa we-PCB?

Ake sidabule inqubo yokubala ububanzi bokulandela obuthile besiginali yamandla edlulisa okwamanje kusuka entweni yamandla iye kudivayisi eyakhelekayo. Kulesi sibonelo, sizobala ububanzi bolayini obuncane bendlela yamandla emoto ye-DC. Indlela yamandla iqala ku-fuse, iwele i-H-bridge (ingxenye esetshenziselwa ukuphatha ukudluliswa kwamandla kuwo wonke ama-motor motor e-DC), futhi inqamulelwa kusixhumi semoto. Isilinganiso samanje samanje esiqhubekayo esidingekayo semoto ye-DC cishe ngama-ampere ama-2.

Manje, izintambo ze-PCB zisebenza njenge-resistor, futhi uma isikhathi eside futhi sincipha i-wiring, ukumelana okuthe xaxa kuyangezwa. Uma i-wiring ingachazwanga kahle, i-current high ingalimaza i-wiring kanye / noma ibangele ukwehla okukhulu kwe-voltage emotweni (okuholele ekwehliseni isivinini). INetC21_2 ekhonjiswe kuMdwebo 3 icishe ibe ngamasentimitha angu-0.8 ubude futhi idinga ukuphatha ubukhulu bamanje bama-ampere ama-2. Uma sicabanga ngezimo ezithile ezijwayelekile, njengokuthululwa okukodwa kokuthusi nokushisa kwegumbi ngesikhathi sokusebenza okujwayelekile, sidinga ukubala ububanzi bomugqa omncane nokwehla kwengcindezi okulindelekile kulobo bubanzi.

Ungabala kanjani ukumelana kwentambo kwe-PCB?

I-equation elandelayo isetshenziselwa ukulandelela indawo:

Indawo [Mils ²] = (yamanje [Amps] / (K * (Temp_Rise [° C]) ^ b)) ^ (1 / C), elandela umbandela wangaphandle wesisekelo se-IPC (noma phezulu / phansi), k = 0.048, b = 0.44, C = 0.725. Qaphela ukuthi okuwukuphela kokuguquguquka esikudinga ngempela ukukufaka kungokwamanje.

Ukusebenzisa lesi sifunda ku-equation elandelayo kuzosinika ububanzi obudingekayo obusitshela ububanzi bomugqa obudingekayo ukuphatha okwamanje ngaphandle kwezinkinga ezingaba khona:

Ububanzi [Mils] = indawo [Mils ^ 2] / (ukujiya [oz] * 1.378 [mils / oz]), lapho u-1.378 ahlobene nosayizi ojwayelekile othululela u-1 oz.

Ngokufaka ama-amperes ama-2 wamanje ekubalweni okungenhla, sithola ubuncane bama-30 mils wentambo.

Kepha lokho akusitsheli ukuthi ukwehla kwamandla kagesi kuzoba yini. Lokhu kubandakanyeka kakhulu ngoba idinga ukubala ukumelana kocingo, okungenziwa ngokuya ngefomula ekhonjiswe kuMdwebo 4.

Kule fomula, ρ = Resistivity yethusi, α = lokushisa Coefficient yethusi, T = trace ukujiya, W = trace ububanzi, L = trace ubude, T = lokushisa. Uma wonke amanani afanele afakwa kubude obungu-0.8 “nobude obungu-30mils, sithola ukuthi ukumelana kwentambo cishe kungu-0.03? Futhi yehlisa i-voltage cishe ngama-26mV, okulungele lolu hlelo lokusebenza. Kuyasiza ukwazi ukuthi yini ethinta la manani.

Isikhala sekhebula le-PCB nobude

Okwakhiwa kwedijithali okunokuxhumana kwejubane eliphezulu, isikhala esithile nobude obuguquliwe kungadingeka ukunciphisa i-crosstalk, coupling, kanye ne-reflection. Ngale njongo, ezinye izinhlelo zokusebenza ezijwayelekile ziyizimpawu ezahlukanisiwe ezenzelwe i-USB namasiginali wokuhlukaniswa asuselwa ku-RAM. Imvamisa, i-USB 2.0 izodinga umzila wokwehluka ku-480Mbit / s (iklasi lejubane le-USB) noma ngaphezulu. Lokhu kungenxa yokuthi i-USB enejubane elikhulu isebenza ngokuvama nokwehluka okuphansi kakhulu, okusondeza ileveli yesiginali jikelele ngomsindo wangemuva.

Kunezinto ezintathu ezibalulekile okufanele uzicabangele lapho uhambisa izintambo ze-USB ezisheshayo: ububanzi bocingo, isikhala sokuhola, nobude bekhebula.

Konke lokhu kubalulekile, kepha okubaluleke kakhulu kokuthathu ukuqinisekisa ukuthi ubude bemigqa emibili buhambisana kakhulu. Njengomthetho ojwayelekile wesithupha, uma ubude bezintambo buhluka komunye nomunye ngokungadluli kuma-50 mils (we-USB esheshayo), lokhu kukhulisa kakhulu ubungozi bokubonisa, okungaholela ekuxhumaneni okungalungile. I-90 ohm impedance efanayo iyincazelo ejwayelekile yokuhlukanisa izintambo zombili. Ukufeza le nhloso, umzila kufanele ulungiselelwe ngobubanzi nangesikhala.

Umdwebo 5 ukhombisa isibonelo sokubhangqa okwehlukile kwezintambo ezihamba ngesivinini ezingena nge-USB eziqukethe izintambo ezi-12 mil ububanzi ngezikhathi ezingama-15 mil.

Izindlela zokuhlangana zezinto ezisuselwa kwimemori eziqukethe izixhumi ezihambisanayo (njenge-DDR3-SDRAM) zizobekelwa umkhawulo ngobude bocingo. Isoftware esezingeni eliphezulu kakhulu ye-PCB izoba namandla okulungiswa kobude enza ngcono ubude bomugqa ukufanisa wonke amasiginali afanele ebhasini elihambisanayo. Umdwebo 6 ukhombisa isibonelo sesakhiwo se-DDR3 ngentambo yokulungisa ubude.

Iminonjana nezindiza zokugcwaliswa komhlaba

Ezinye izinhlelo ezinezinto ezizwakala umsindo, njengama-chips angenantambo noma ama-antenna, zingadinga ukuvikelwa okwengeziwe. Ukuklama izintambo nezindiza ezinezimbobo zomhlaba ezishumekiwe kungasiza kakhulu ekunciphiseni ukuhlangana kwezintambo eziseduze noma ukukha izindiza nezimpawu ezingekho ebhodini ezingena emaphethelweni ebhodi.

Umdwebo 7 ukhombisa isibonelo semodyuli ye-Bluetooth ebekwe eduze komphetho wepuleti, ne-antenna yayo (nge-screen ephrintiwe “ANT”) ngaphandle komugqa ojiyile oqukethe izimbobo ezigxunyekwe ezixhumene nokwakheka komhlaba. Lokhu kusiza ukuhlukanisa i-antenna kwamanye amasekethe ezindiza nezindiza.

Le ndlela ehlukile yokuhamba ngomhlabathi (kulokhu ibhanoyi elihamba ngamacala amaningi) ingasetshenziswa ukuvikela isekethe lebhodi kwizimpawu zangaphandle ezingenantambo zebhodi. Umdwebo 8 ukhombisa i-PCB ezwakala umsindo enendiza efakwe ngaphakathi emgodini eceleni komngcele webhodi.

Izindlela ezihamba phambili zokwenza izintambo ze-PCB

Izici eziningi zinquma izici zentambo zensimu ye-PCB, ngakho-ke qiniseka ukuthi ulandela imikhuba emihle lapho uxhuma i-PCB yakho elandelayo, futhi uzothola ibhalansi phakathi kwezindleko ze-PCB fab, ukuminyana kwesekethe, kanye nokusebenza kukonke.