A kiyaye waɗannan wuraren wayoyi na PCB a zuciya

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Bayanin samfur:

1. Yawan aiki

A cikin ƙira ta PCB, don yin ƙira mafi girman ƙirar allo mai ma'ana, mafi kyawun aikin hana tsangwama, yakamata a yi la'akari da waɗannan abubuwan:

(1) Madaidaicin zaɓi na yadudduka Lokacin zazzage allunan kewayawa mai ƙarfi a cikin ƙirar PCB, ana amfani da jirgin sama na ciki a tsakiya azaman iko da ƙasa Layer, wanda zai iya taka rawar garkuwa, yadda ya kamata ya rage inductance parasitic, gajarta tsawon lokaci. layukan sigina, da rage tsangwama tsakanin sigina.

(2) Yanayin kewayawa dole ne ya kasance daidai da 45° Juyin kusurwa ko jujjuyawar baka, wanda zai iya rage fitar da sigina mai girma da haɗin kai.

(3) Tsawon igiya Mafi guntu tsawon na USB, mafi kyau.Matsakaicin tazarar daidaici tsakanin wayoyi biyu, mafi kyau.

(4) Yawan ta ramuka Ƙananan adadin ta ramuka, mafi kyau.

(5) Jagoran wayoyi na tsaka-tsakin ya kamata ya zama a tsaye, wato, saman saman yana kwance, saman ƙasa yana tsaye, don rage tsangwama tsakanin sakonni.

(6) Copper shafi ƙara grounding tagulla shafi na iya rage tsangwama tsakanin sakonni.

(7) Ƙaddamar da mahimmancin siginar siginar siginar, na iya inganta haɓakar ikon sigina na sigina, ba shakka, kuma yana iya zama haɗakar da sarrafa tushen tsoma baki, ta yadda ba zai iya tsoma baki tare da wasu sigina ba.

(8) Kebul na sigina ba sa hanyar sigina a madaukai.Sigina na hanya a yanayin sarkar Daisy.

2. fifikon wayoyi

Babban fifikon layin sigina: ƙaramin siginar analog, siginar sauri mai sauri, siginar agogo da siginar aiki tare da sauran siginonin fifikon wayoyi.

Ƙa'ida ta farko mai yawa: Fara wayoyi daga mafi hadaddun haɗin kan allo.Fara wayoyi daga mafi yawan wayoyi masu yawa na allon

Abubuwan lura:

A. Gwada samar da layin waya na musamman don maɓalli na maɓalli kamar siginar agogo, sigina mai tsayi da sigina masu mahimmanci, kuma tabbatar da mafi ƙarancin yankin madauki.Idan ya cancanta, ya kamata a ɗauki fifikon wayoyi, garkuwa da haɓaka tazarar aminci.Tabbatar da ingancin sigina.

b.Yanayin EMC tsakanin layin wutar lantarki da ƙasa ba shi da kyau, don haka ya kamata a guji sigina masu kula da tsangwama.

c.Ya kamata a yi amfani da hanyar sadarwa tare da buƙatun sarrafa impedance gwargwadon yiwuwa gwargwadon tsayin layi da buƙatun faɗin layi.

3, wayar agogo

Layin agogo shine ɗayan manyan abubuwan da ke shafar EMC.Yi ƴan ramuka kaɗan a cikin layin agogo, guje wa tafiya tare da sauran layin sigina gwargwadon yuwuwa, kuma ku nisanci layukan sigina na gabaɗaya don guje wa tsoma baki tare da layukan sigina.A lokaci guda kuma, ya kamata a guji samar da wutar lantarki a kan allo don hana tsangwama tsakanin wutar lantarki da agogo.

Idan akwai guntu na musamman na agogo a kan jirgin, ba zai iya shiga ƙarƙashin layin ba, ya kamata a dage farawa a ƙarƙashin jan karfe, idan ya cancanta, kuma zai iya zama na musamman ga ƙasarsa.Don yawancin oscillator na guntu na kristal, waɗannan oscillator ɗin bai kamata su kasance ƙarƙashin layi ba, don sanya wariyar jan ƙarfe.

4. Layi a kusurwar dama

Ana buƙatar cabing na kusurwar dama gabaɗaya don guje wa halin da ake ciki a cikin wayar PCB, kuma ya kusan zama ɗaya daga cikin ma'auni don auna ingancin wayoyi, to yaya tasirin igiyoyin kusurwar dama za su yi kan watsa sigina?A ka'ida, kewayawa na kusurwar dama zai haifar da nisa na layin watsawa don canzawa, yana haifar da katsewa.A zahiri, ba kawai madaidaiciyar Angle ba, ton Angle, m Angle routing na iya haifar da canje-canjen impedance.

Tasirin kewayawa na kusurwar dama akan sigina yana nunawa a cikin abubuwa uku:

Na farko, kusurwa na iya zama daidai da nauyin capacitive a kan layin watsawa, rage jinkirin lokacin tashi;

Na biyu, dakatarwar impedance zai haifar da tunanin sigina;

Na uku, EMI ta samar da tip kusurwar dama.

5. Mugun kwana

(1) Don babban mita na halin yanzu, lokacin da jujjuyawar waya ta gabatar da kusurwar dama ko ma madaidaicin kusurwa, kusa da kusurwar, ƙarfin ƙarfin maganadisu da ƙarfin filin lantarki yana da girma, zai haskaka igiyoyin lantarki mai ƙarfi, da inductance. Anan zai kasance ingantacciyar girma, inductive zai fi girma fiye da kusurwar obtuse ko kusurwa mai zagaye.

(2) Don na'urar bas na da'irar dijital, kusurwar wayoyi ba ta da kyau ko ta zagaye, yanki na wayoyi yana da ƙananan ƙananan.Ƙarƙashin yanayin tazarar layi ɗaya, jimlar tazarar layin tana ɗaukar ƙasa da nisa sau 0.3 fiye da juya kusurwar dama.

6. Daban-daban kwatance

Cf.Waya daban-daban da matching impedance

Ana amfani da siginar Bambanci sosai a cikin ƙira na da'irori masu sauri, saboda mafi mahimmancin sigina a cikin da'irori koyaushe suna amfani da tsari na banbanta.Ma'anar: A cikin harshen turanci a sarari, yana nufin cewa direba ya aika da sigina guda biyu daidai, inverting, kuma mai karɓa yana tantance ko yanayin ma'ana shine "0" ko "1" ta hanyar kwatanta bambanci tsakanin ƙarfin biyun.Biyu da ke ɗauke da siginar banbanta ana kiran su da kewayawa daban-daban.

Idan aka kwatanta da na yau da kullun na sigina mai ƙarewa guda ɗaya, siginar bambance-bambance yana da fa'idodi mafi bayyane a cikin abubuwa uku masu zuwa:

a.Ƙarfin hana tsangwama, saboda haɗakar da ke tsakanin wayoyi daban-daban guda biyu yana da kyau sosai, idan akwai tsangwama daga waje, kusan an haɗa shi da layi biyu a lokaci guda, kuma mai karɓa yana kula da kawai bambancin dake tsakanin sigina biyu, don haka za a iya soke hayaniyar gama gari daga waje gaba ɗaya.

b.zai iya hana EMI yadda ya kamata.Hakazalika, saboda polarity na sigina biyu sun saba, filayen lantarki da suke haskakawa na iya soke juna.Matsakaicin kusancin, ƙarancin ƙarfin lantarki da ake fitarwa zuwa duniyar waje.

c.Madaidaicin sakawa lokaci.Tun da sauyawar canje-canje na sigina daban-daban suna samuwa a mahadar sigina guda biyu, sabanin sigina na yau da kullun masu ƙarewa guda ɗaya waɗanda ke dogara ga babban ƙarfin wuta da ƙarancin ƙima, tasirin fasaha da zafin jiki kaɗan ne, wanda zai iya rage kurakurai a cikin lokaci kuma yana da ƙari. dace da da'irori tare da ƙananan sigina amplitude.LVDS (ƙananan siginar bambancin wutar lantarki), wanda ya shahara a halin yanzu, yana nufin wannan ƙaramar fasahar sigina ta ƙarami.

Ga injiniyoyin PCB, abu mafi mahimmanci shine tabbatar da cewa za'a iya amfani da fa'idodin hanyoyin bambance-bambancen a cikin ainihin hanyar.Watakila idan dai tuntuɓar mutanen Layout za su fahimci gabaɗayan buƙatun na tuƙi daban-daban, wato, “daidai tsayi, daidai tazara”.

Tsawon daidaici shine don tabbatar da cewa siginar banbance-banbance guda biyu suna kiyaye kishiyar polarity a kowane lokaci kuma a rage sashin yanayin gama gari.Daidaitawa shine yafi don tabbatar da cewa bambance-bambancen impedance daidai ne kuma rage tunani."Kusa da yuwuwa" wani lokacin buƙatu ne don bambance-bambance.

7. Layin maciji

Layin Serpentine wani nau'i ne na Layout wanda galibi ana amfani da shi wajen shimfidawa.Babban manufarsa shine daidaita jinkiri da kuma biyan bukatun tsarin tsarin lokaci.Abu na farko da masu zanen kaya ya kamata su gane shi ne cewa wayoyi masu kama da maciji na iya lalata ingancin sigina da canza jinkirin watsawa, kuma ya kamata a guji lokacin da ake yin waya.Duk da haka, a cikin ainihin ƙira, don tabbatar da isasshen lokacin riƙe da sigina, ko don rage lokacin kashewa tsakanin rukuni ɗaya na sigina, sau da yawa ya zama dole don iska da gangan.

Abubuwan lura:

Nau'i-nau'i na layukan sigina daban-daban, gabaɗaya layikan layi ɗaya, kaɗan gwargwadon yuwuwar ta cikin rami, dole ne a buga su, su kasance layi biyu tare, don cimma daidaiton impedance.
Ƙungiyar bas ɗin da ke da halaye iri ɗaya ya kamata a fatattake su tare da juna gwargwadon iyawa don cimma tsayi daidai.Ramin da ke kaiwa daga kushin facin yana da nisa da kushin gwargwadon yiwuwa.