Everyone knows doing the principle diagram of the PCB is designed into a real piece of PCB, please don’t look down upon this process, there are a lot of things on the principle of practicable in engineering has difficult to achieve, or something that someone can achieve them,but others can not, so it is not difficult to make a PCB, but make a good PCB jirgin ba mai sauki abu.
Biyu manyan matsaloli a filin na microelectronics ne high mita siginar da kuma raunana siginar aiki, PCB samar da matakin ne da muhimmanci musamman a wannan girmamawa, da wannan manufa zane, wannan gyara, mutane daban-daban sanya PCB zai yi daban-daban sakamakon, don haka yadda za a yi mai kyau PCB jirgin? kafa a kan mu baya kwarewa, za mu so su tattauna da mu ra'ayoyinsu kan wadannan fannoni:
1. Ƙayyade raga
Samu wani zane aiki, dole ne da farko share zane a raga, shi ne Common PCB jirgin , high-mita PCB , kananan siginar aiki PCB ko akwai biyu high mita da kuma kananan siginar aiki na PCB, idan shi ne mai kowa PCB , kamar yadda dogon kamar yadda ka yi m layout da kuma shirya, inji size m, Idan kaya layi da kuma dogon layin, za a abar kulawa da wani wajen, sauƙaƙa load, don ƙarfafa dogon layi na drive, da key shi ne su hana dogon layi ta tunani. lokacin da akwai fiye da 40MHz alama Lines a kan jirgin, musamman sharudda suna sanya wadannan alama Lines, kamar crosstalk.If mita ne mafi girma, da more ƙuntatawa akan tsawon na wayoyi, bisa ga rarraba sigogi na cibiyar sadarwa ka'idar, da hulda tsakanin babban gudun kewaye da aka makala ne hukunci factor, da tsarin ba za a iya watsi da a design.With kyautata na ƙofar watsa gudun, a kan layi da zai kara, da crosstalk tsakanin m siginar Lines zai zama gwargwado ga karuwa a, yawanci high-gudun ikon amfani da zafin rana masha'a da kewaye ne sosai babban, kamata sa isa hankali lokacin da yin high-gudun PCB.
Lokacin da jirgin da millivolt matakin ko microvolt matakin a lokacin da rauni sigina, da alama za bukatar kula na musamman, kananan siginar da take da rauni žwarai, sosai m zuwa wasu karfi siginar tsangwama, da tsare matakan ne sau da yawa zama dole, in ba haka ba zai ƙwarai rage siginar-to-amo ratio.So cewa amfani sakonni ana nutsar da fitar da amo da kuma ba za a iya yadda ya kamata cirewa.
A kan jirgin mũdu ma ya kamata a dauka cikin la'akari da lokacin da zane lokaci, jiki da wuri na gwajin maki, gwajin batu na kadaici dalilai ba za a iya watsi da, saboda wasu daga cikin kananan siginar da kuma high mita siginar da aka ba kai tsaye ƙara bincike don auna.
Bugu da kari, akwai sauran related dalilai, kamar Layer na allon, da kunshin siffar da aka gyara da kuma inji ƙarfi daga cikin boards.Before yin PCB allon, ya kamata ka yi zane manufa a hankali.
2. Fahimci bukatun da aiki na gyara amfani a cikin layout
Kamar yadda muka sani, akwai wasu na musamman aka gyara a cikin layout sun musamman bukatun, kamar LOTI da APH amfani analog sigina amfilifa, analog sigina amfilifa ga ikon da ake bukata domin santsi, kananan ripple.The kwaikwaiyo na kananan siginar sassa kamata a kiyaye daga ikon devices.On da Oti jirgin, da kananan siginar karawa part aka kuma musamman tsara da tsare mask zuwa garkuwa da kau- electromagnetic interference.GLINK kwakwalwan kwamfuta amfani a cikin NTOI jirgin ne ECL tsari, ikon amfani babban zazzabi, to matsalar zafi masha'a dole ne a gudanar lokacin da layout dole ne na musamman shawara, idan na halitta sanyaya, zai sa a GLINK guntu a iska ya kwarara ne m, kuma daga cikin zãfi ne ba banbanci zuwa wasu chips.If akwai wani Kakakin ko wasu high ikon na'urar a kan jirgin, zai iya yiwuwa ma sa tsanani gurbatawa na da ikon ya kamata ma biya isa hankali.
3. shawara na bangaren layout
A layout na gyara na farko daya factor yi la'akari ne da yi, a hankali alaka da connection aka gyara tare har zuwa yiwu, musamman ga wasu high gudun line, da layout ne su sa shi a matsayin takaice kamar yadda zai yiwu a raba ikon siginar da kananan sigina device.In da Jigo na ganawa da wasan kwaikwayon na kewaye, shi ne kuma dole a yi la'akari da tsari na gyara domin, da kyau, m to gwada, da inji size na hukumar, da matsayi na soket, da dai sauransu
The watsa jinkirta lokacin grounding da kuma musayar a high-gudun tsarin ne kuma na farko factor da za a gani a lokacin da zayyana da system.Signal a kan watsa lokaci ya yi da babban tasiri a kan sauran tsarin gudun, musamman ga high-gudun ECL haihuwarka, ko da yake high gudun Hadakar kewaye block kanta, amma a sakamakon a kasa tare da kowa sauti (kowace 30 cm tsawo, game da bata lokaci ba na 2 ns) kawo karuwa da bata lokaci lokaci, za a iya sa tsarin gudun aka ƙwarai rage. Kamar motsi littãfi, synchronous counter wannan aiki tare aiki sassa a wannan yanki na katin, mafi kyau saboda daban-daban baza bata lokaci lokaci na Agogon alama a kan jirgin ne ba su daidaita, kuma zai iya haifar da wani motsi littãfi kayan kurakurai, idan ba a kan wani farantin, inda aiki tare ne da key, daga jama'a agogon tushen haɗa ta agogon line dole ne daidaita da tsayin daga cikin jirgin.
4. la'akari da wayoyi
Tare da zane na OTNI kuma star Tantancewar fiber cibiyar sadarwa, fiye da 100MHz da babban gudun siginar line za bukatar da za a tsara a nan gaba. Wasu asali Concepts na babban gudun line za a gabatar a nan.
transmission line
Duk wani "dogon" sigina hanya a kan wani buga kewaye hukumarza a iya daukan wani watsa line.If watsa bata lokaci na line ne da ya fi guntu fiye da siginar da Yunƙurin lokaci, da tunani na mai a lokacin da sigina Yunƙurin zai zama submerged.No ƙara bayyana overshoot, recoil da ringing, domin a wannan lokacin, mafi yawan MOS kewaye, saboda Yunƙurin lokacin line watsa bata lokaci lokaci ne da yawa girma, don haka zai iya zama a cikin mita tsawo da kuma babu sigina distortion.And for sauri dabaru haihuwarka, musamman matsananci-high gudun ECL.
A cikin hali na Hadakar haihuwarka, da tsawon da burbushi dole ne a iya muhimmanci taqaitaccen domin ya kula da mutuncin da sigina saboda sauri gefe gudu.
Akwai hanyoyi biyu don sa high-gudun kewaye a gwada dogon layi aiki ba tare da tsanani murdiya, da ake amfani da m dakushe baki TTL schottky diode clamping hanya, yin turu zama hani a wani diode ne m fiye da ƙasa m matsa lamba drop a kan matakin rage recoil a baya na amplitude, da hankali mafitar gefen overshoot an yarda, amma shi ne matakin "H" a jihar gwada da high fitarwa impedance na kewaye (50 ~ 80 Ω) attenuation .Bugu da kari, saboda da matakin na "H" jiha rigakafi, ya fi girma recoil matsala ba sosai fice, na'urar na HCT jerin, idan ta amfani da schottky diode clamping da jerin juriya gefen connect da hanyar, ingantattun sakamako zai zama mafi bayyananne.
Lokacin da akwai wani fan fita tare da siginar line, da TTL siffata Hanyar aka bayyana a sama da aka rasa a cikin mafi girma bit kudi da kuma sauri baki speed.Because akwai ake nuna taguwar ruwa a cikin line, za su ayan da za a hada a high kudi, haka haddasa tsanani murdiya na siginar da ragewa anti-tsangwama ability.Therefore, domin warware matsalar tunani, wani hanyar mafi yawa ana amfani da shi a ECL tsarin: line impedance matching method.In wannan hanya da tunani ne sarrafawa da kuma mutuncin siginar da aka tabbatar.