The zane na PCB mai girma tsari ne mai rikitarwa, kuma abubuwa da yawa na iya yin tasiri kai tsaye akan aikin aiki na da’ira mai tsayi. Ƙirar da’ira mai girma-girma da wayoyi suna da mahimmanci ga dukan ƙira. Nasiha goma masu zuwa don ƙirar PCB mai tsayi mai tsayi ana ba da shawarar musamman:

1. Multilayer allon waya

Maɗaukakin maɗaukakiyar da’irori yakan sami babban haɗin kai da babban yawan wayoyi. Yin amfani da allunan nau’i-nau’i masu yawa ba kawai wajibi ne don yin amfani da waya ba, amma har ma hanya mai mahimmanci don rage tsangwama. A cikin matakin PCB Layout, zaɓi mai ma’ana na girman allo da aka buga tare da takamaiman adadin yadudduka na iya yin cikakken amfani da tsaka-tsakin Layer don saita garkuwa, mafi kyawun fahimtar ƙasa mafi kusa, da kuma rage tasirin parasitic yadda ya kamata kuma rage siginar. Tsawon watsawa, yayin da yake ci gaba da girma Duk waɗannan hanyoyin suna da fa’ida ga amincin da’irori masu tsayi, kamar girman raguwar tsangwama na sigina. Wasu bayanai sun nuna cewa lokacin da aka yi amfani da abu ɗaya, ƙarar allon mai Layer hudu yana da 20dB ƙasa da na allon mai gefe biyu. Duk da haka, akwai kuma matsala. Mafi girman adadin rabin-yadudduka na PCB, mafi rikitarwa tsarin masana’antu, kuma mafi girman farashin naúrar. Wannan yana buƙatar mu zaɓi allunan PCB tare da adadin yadudduka masu dacewa yayin aiwatar da shimfidar PCB. Shirye-shiryen shimfidar abubuwa masu ma’ana, da amfani da madaidaitan ka’idojin wayoyi don kammala ƙira.

2. Ƙarƙashin gubar yana lanƙwasa tsakanin fil ɗin na’urorin lantarki masu sauri, mafi kyau

Wayar jagorar na’urar da’ira mai girma ta fi dacewa don ɗaukar cikakken layin madaidaiciya, wanda ke buƙatar juyawa. Ana iya jujjuya shi da layin karya mai digiri 45 ko madauwari baka. Ana amfani da wannan buƙatu kawai don haɓaka ƙarfin daidaitawar foil ɗin tagulla a cikin ƙananan da’irori, yayin da a cikin da’irori masu girma, ana biyan wannan buƙatu. Buƙatu ɗaya na iya rage fitar da hayaƙi na waje da haɗa juna na sigina masu tsayi.

3. Mafi guntu gubar tsakanin fil na na’urar kewayawa mai girma, mafi kyau

Ƙarfin radiation na siginar ya yi daidai da tsawon alamar siginar. Yayin da babban siginar siginar ya fi tsayi, mafi sauƙin shine haɗawa da abubuwan da ke kusa da shi. Don haka, don agogon sigina, oscillator crystal, bayanan DDR, layin LVDS, layin USB, layin HDMI da sauran manyan layukan sigina ana buƙatar su zama gajere gwargwadon yiwu.

4. Ƙarƙashin madaurin gubar tsakanin fil ɗin na’urar da’ira mai tsayi, mafi kyau

Abin da ake kira “ƙananan canjin tsaka-tsaki na jagorar, mafi kyau” yana nufin cewa ƙananan vias (Via) da aka yi amfani da su a cikin tsarin haɗin kai, mafi kyau. A cewar gefen, daya via iya kawo game da 0.5pF rarraba capacitance, da kuma rage yawan vias iya muhimmanci ƙara gudun da kuma rage yiwuwar data kurakurai.

5. Kula da “crosstalk” da aka gabatar da siginar siginar a cikin layi daya kusa

Ya kamata a kula da wayoyi masu tsayi mai tsayi zuwa “crosstalk” wanda aka gabatar ta hanyar layin sigina na kusa. Crosstalk yana nufin al’amarin haɗuwa tsakanin layin siginar da ba a haɗa kai tsaye ba. Tunda ana watsa sigina masu girma a cikin nau’i na igiyoyin lantarki na lantarki tare da layin watsawa, layin siginar zai yi aiki a matsayin eriya, kuma za a fitar da makamashin filin lantarki a kusa da layin watsawa. Ana haifar da siginonin amo da ba a so saboda haɗin kai na filayen lantarki tsakanin sigina. Ana kiranta crosstalk (Crosstalk). Ma’auni na Layer na PCB, tazarar layukan sigina, halayen lantarki na ƙarshen tuƙi da ƙarshen karɓa, da hanyar ƙarewar layin siginar duk suna da takamaiman tasiri a kan hanyar sadarwa. Don haka, don rage ƙwaƙƙwaran sigina masu girma, ana buƙatar yin waɗannan gwargwadon yiwuwar lokacin da ake yin wayoyi:

Idan sararin waya ya ba da izini, shigar da waya ta ƙasa ko jirgin ƙasa tsakanin wayoyi biyu tare da mafi munin magana na iya taka rawa wajen keɓancewa da rage yawan magana. Lokacin da akwai filin lantarki na lokaci-lokaci a sararin samaniya da ke kewaye da layin siginar, idan ba za a iya kauce wa rarraba daidaitattun ba, za a iya shirya babban yanki na “ƙasa” a gefen gefen layin siginar layi daya don rage tsangwama.

Ƙarƙashin tsarin da sararin waya ya ba da izini, ƙara tazara tsakanin layin siginar da ke kusa, rage madaidaicin tsayin layin sigina, da ƙoƙarin sanya layin agogo daidai da layin siginar maɓalli maimakon layi ɗaya. Idan layin layi daya a cikin layi daya ya kusan ba zai yuwu ba, a cikin yadudduka biyu kusa da su, dole ne kwatancen wayoyi su kasance daidai da juna.

A cikin da’irori na dijital, siginonin agogo na yau da kullun sune sigina tare da sauye-sauyen gefen sauri, waɗanda ke da babban taɗi na waje. Don haka, a cikin ƙirar, ya kamata a kewaye layin agogo da layin ƙasa kuma a buga ƙarin ramukan layin ƙasa don rage ƙarfin da aka rarraba, ta yadda za a rage yawan magana. Don manyan agogon sigina, yi ƙoƙarin yin amfani da siginonin agogo mai ƙarancin ƙarfin wuta da kunsa yanayin ƙasa, kuma kula da amincin fakitin ƙasan naushi.

Kada a dakatar da tashar shigarwar da ba a yi amfani da ita ba, amma ta ƙasa ko kuma ta haɗa ta da wutar lantarki (mafin wutar lantarki kuma yana ƙasa a madaidaicin siginar sigina), saboda layin da aka dakatar zai iya zama daidai da eriya mai watsawa, kuma ƙasa na iya hanawa. watsin. Aiki ya tabbatar da cewa yin amfani da wannan hanya don kawar da maganganun giciye na iya haifar da sakamako nan da nan.

6. Ƙara capacitor mai girma-mita zuwa ga fil ɗin samar da wutar lantarki na haɗin haɗin da’irar

Ana ƙara babban madaidaicin decoupling capacitor zuwa fil ɗin samar da wutar lantarki na kowane haɗaɗɗiyar shingen da’ira a kusa. Haɓaka babban madaidaicin decoupling capacitor na fil ɗin samar da wutar lantarki zai iya murkushe tsangwama na babban mitar masu jituwa akan fil ɗin wutar lantarki.

7. Ware wayar ƙasa na siginar dijital mai girma da siginar siginar analog

Lokacin da aka haɗa wayar ƙasa ta analog, waya ta ƙasa ta dijital, da sauransu. Ƙarfin ƙasa na wayar ƙasa na siginar dijital mai girma gabaɗaya bai dace ba. Sau da yawa akwai wani takamaiman ƙarfin lantarki tsakanin su biyun kai tsaye. Bugu da ƙari, wayar ƙasa na siginar dijital mai girma sau da yawa yana ƙunshe da abubuwa masu jituwa sosai na siginar mai girma. Lokacin da wayar ƙasa ta siginar dijital da siginar siginar analog ɗin siginar ƙasa ke haɗa kai tsaye, jituwar siginar babban mitar za ta tsoma baki tare da siginar analog ta hanyar haɗa wayar ƙasa. Sabili da haka, a cikin yanayi na al’ada, za a keɓance wayar ƙasa na siginar dijital mai girma da kuma waya ta ƙasa na siginar analog, kuma ana iya amfani da hanyar haɗin kai mai lamba ɗaya a matsayi mai dacewa, ko kuma hanyar da ta dace. Za’a iya amfani da haɗin haɗin gwiwar mitar shake Magnetic bead.

8. Guji madaukai da aka kafa ta hanyar wayoyi

Duk nau’ikan alamun sigina mai tsayi bai kamata su samar da madauki gwargwadon iko ba. Idan ba zai yuwu ba, yankin madauki ya kamata ya zama ƙarami gwargwadon yiwuwa.

9. Dole ne a tabbatar da ingantaccen siginar impedance daidai

A cikin tsarin watsa siginar, lokacin da impedance bai dace ba, siginar za ta yi nuni a cikin tashar watsawa, kuma tunani zai sa siginar da aka haɗa ta haifar da overshoot, yana haifar da sigina don canzawa kusa da madaidaicin ma’auni.

Muhimmin hanyar kawar da tunani shine dacewa da rashin daidaituwar siginar watsawa da kyau. Tun da mafi girma da bambanci tsakanin ma’aunin nauyi da kuma halayen halayen layin watsawa, mafi girman tunani, don haka halayen halayen siginar siginar ya kamata a yi daidai da nauyin nauyin nauyi kamar yadda zai yiwu. A lokaci guda, da fatan za a lura cewa layin watsawa akan PCB ba zai iya samun canje-canje kwatsam ko sasanninta ba, kuma kuyi ƙoƙarin kiyaye impedance na kowane batu na layin watsawa, in ba haka ba za a sami tunani tsakanin sassa daban-daban na layin watsawa. Wannan yana buƙatar cewa yayin wayar PCB mai sauri, dole ne a kiyaye waɗannan ka’idodin wiring:

Dokokin kebul na waya. Yana buƙatar rarrabuwar siginar USB, faɗin layin shine 10mil, tazarar layin shine 6mil, layin ƙasa da tazarar layin sigina shine 6mil.

Ka’idojin wiring na HDMI. Ana buƙatar bambance-bambancen siginar HDMI, faɗin layin shine mil 10, tazarar layin shine mil 6, kuma tazara tsakanin kowane nau’ikan siginar banbanta na HDMI ya wuce mil 20.

Dokokin wayoyi na LVDS. Yana buƙatar bambance-bambancen siginar LVDS, faɗin layin shine 7mil, tazarar layin shine 6mil, manufar ita ce sarrafa bambance-bambancen siginar HDMI zuwa 100+-15% ohm

DDR wayoyi dokokin. Alamun DDR1 suna buƙatar sigina don kada su bi ta ramuka gwargwadon yuwuwar, layukan sigina suna da faɗi daidai, kuma layukan suna da sarari daidai gwargwado. Dole ne alamun su hadu da ka’idar 2W don rage yawan magana tsakanin sigina. Don na’urori masu sauri na DDR2 da sama, ana kuma buƙatar bayanai mai tsayi. Layukan suna daidai da tsayi don tabbatar da madaidaicin siginar.

10. Tabbatar da ingancin watsawa

Kula da amincin watsa siginar kuma hana “la’akarin billa ƙasa” wanda ya haifar da tsagawar ƙasa.