Layout ndeimwe yeanonyanya kukosha basa hunyanzvi hwePCB dhizaini mainjiniya. Unhu hwe wiring huchakanganisa zvakananga kushanda kwehurongwa hwose. Mazhinji epamusoro-kumhanya dhizaini dzidziso dzinofanirwa kupedzisira dzaitwa uye kusimbiswa kuburikidza neRayout. Zvinogona kuonekwa kuti wiring inokosha zvikuru mukati yakakwira-kumhanya pcb design. Izvi zvinotevera zvinoongorora kurongeka kwemamwe mamiriro angangosangana nawo mune chaiyo wiring, uye kupa mamwe akakwenenzverwa nzira dzekufambisa.

Iyo inonyanya kutsanangurwa kubva kune matatu maficha: kurudyi-kona wiring, differential wiring, uye serpentine wiring.

1. Right-angle routing

Kurudyi-kona wiring kazhinji imamiriro ezvinhu anoda kudzivirirwa zvakanyanya sezvinobvira muPCB wiring, uye yatove imwe yemayero ekuyera kunaka kwewaya. Saka ingani pesvedzero ichave nerudyi-angle wiring pane chiratidzo chekufambisa? Muchidimbu, nzira yekurudyi-kona inoshandura upamhi hwemutsara weiyo tambo yekutapurirana, zvichikonzera kusaenderera mberi mu impedance. Muchokwadi, kwete chete kurudyi-kona nzira, asiwo makona uye acute-angle routing inogona kukonzera impedance shanduko.

Kurudziro yekurudyi-kona nzira pachiratidzo inonyanya kuratidzwa muzvikamu zvitatu:

Imwe ndeyokuti kona inogona kuenzana ne capacitive load pamutsetse wekutumira, iyo inoderedza nguva yekukwira; chechipiri ndechekuti iyo impedance discontinuity ichakonzera chiratidzo chekuratidzira; yechitatu ndiyo EMI inogadzirwa nekurudyi-kona tipi.

Iyo parasitic capacitance inokonzerwa nekona yekurudyi yetambo yekufambisa inogona kuverengerwa neinotevera empirical formula:

C = 61W (Er) 1/2 / Z0

Mune fomula iri pamusoro, C inoreva kuenzana kugona kwekona (unit: pF), W inoreva hupamhi hweiyo trace (yuniti: inch), εr inoreva dielectric garage yepakati, uye Z0 ndiyo hunhu impedance. yemutsetse wekutakurisa. Semuenzaniso, ye4Mils 50 ohm transmission line (er is 4.3), capacitance inounzwa nekona yekurudyi ingangoita 0.0101pF, uyezve shanduko yenguva yekusimuka yakakonzerwa neizvi inogona kufungidzirwa:

T10-90%=2.2CZ0/2=2.20.010150/2=0.556ps

Zvinogona kuonekwa kuburikidza nekuverenga kuti capacitance effect yakaunzwa ne-right angle trace idiki zvakanyanya.

Sezvo mutsara wehupamhi hwekona-yekona trace ichiwedzera, iyo impedance ipapo inoderera, saka imwe chiratidzo chekuratidzira chiitiko chichaitika. Isu tinokwanisa kuverenga iyo yakaenzana impedance mushure mehupamhi hwemutsara huchiwedzera zvinoenderana neiyo impedance calculation formula inotaurwa mumutsara wemutsara chitsauko, uye tozoverenga iyo yekuratidzira coefficient zvinoenderana neempirical formula:

ρ=(Zs-Z0)/(Zs+Z0)

Kazhinji, iyo impedance shanduko inokonzerwa nekurudyi-kona wiring iri pakati pe7% -20%, saka iyo yakanyanya kuratidza coefficient inenge 0.1. Uyezve, sezvinogona kuonekwa kubva pamufananidzo uri pasi apa, iyo impedance yetambo yekufambisa inoshanduka kusvika padiki mukati mehurefu hweW / 2 mutsara, uye inodzokera kune yakajairwa impedance mushure menguva yeW / 2. Iyo yese impedance shanduko nguva ipfupi zvakanyanya, kazhinji mukati me10ps. Mukati, shanduko dzinokurumidza uye diki dzakadaro dzinenge dzisina basa pakufambiswa kwemasaini.

Vanhu vazhinji vane kunzwisisa uku kwekurudyi-kona wiring. Ivo vanofunga kuti muromo uri nyore kufambisa kana kugamuchira mafungu emagetsi uye kugadzira EMI. Ichi chave chimwe chezvikonzero nei vanhu vazhinji vachifunga kuti kurudyi-kona wiring haigone kufambiswa. Nekudaro, mazhinji chaiwo ebvunzo mhinduro anoratidza kuti kurudyi-angled traces haiburitse pachena EMI pane mitsara yakatwasuka. Zvichida kushanda kwechiridzwa chemazuva ano uye chiyero chekuedza chinodzivisa kurongeka kwemuedzo, asi zvinoratidzira dambudziko. Mwaranzi yewaya yekona-yekurudyi yatove idiki pane kuyerwa kukanganisa kwechiridzwa pachayo.

Muzhinji, iyo yekurudyi-kona routing haina kutyisa sezvainofungidzirwa. Zvirinani mumashandisirwo ari pasi peGHz, chero mhedzisiro senge capacitance, kuratidza, EMI, nezvimwe hazviratidzike mukuedzwa kweTDR. High-speed PCB dhizaini mainjiniya anofanirwa kuramba akatarisa pane dhizaini, simba / pasi dhizaini, uye wiring dhizaini. Via maburi uye zvimwe zvinhu. Ehe, kunyangwe kukanganisa kwekurudyi-kona wiring hakuna kunyanyisa, hazvireve kuti isu tese tinogona kushandisa kurudyi-kona wiring mune ramangwana. Kutarisa kune zvakadzama ndihwo hwakakosha hunhu hunofanirwa kuve nahwo mainjiniya akanaka. Uyezve, nekukurumidza kukura kwemaseketi edhijitari, PCB Iyo frequency yechiratidzo inogadziriswa nemainjiniya icharamba ichiwedzera. Mumunda weRF dhizaini pamusoro pe10GHz, aya madiki ekurudyi angles anogona kuve akatarisana neakakwira-kumhanya matambudziko.

2. Yakasiyana nzira

Chiratidzo chakasiyana (DifferentialSignal) chinowedzera uye chinoshandiswa zvakanyanya mukukwirira-kumhanya dhizaini dhizaini. Chiratidzo chinonyanya kukosha munharaunda inowanzogadzirwa nemhando yakasiyana-siyana. Chii chinoita kuti rikurumbire kudaro? Maitiro ekuve nechokwadi chekuita kwayo kwakanaka muPCB dhizaini? Nemibvunzo miviri iyi, tinoenderera mberi kune chikamu chinotevera chehurukuro.

Chii chinonzi chiratidzo chekusiyanisa? Mukutaura kwevaraidzo, magumo ekutyaira anotumira maviri akaenzana uye akapidiguka masaini, uye magumo ekugamuchira anotonga iyo logic mamiriro “0” kana “1” nekuenzanisa mutsauko uripo pakati pemagetsi maviri. Iwo maronda maviri anotakura zviratidzo zvekusiyanisa anonzi matsariro akasiyana.

Kuenzaniswa neakajairwa-anopera-anopera masaini masaini, masaini masaini ane akanyanya kunaka mabhenefiti mune anotevera maficha matatu:

a. Kwakasimba kupesana-kupindira kugona, nekuti kubatanidza pakati pematanho maviri ekusiyanisa kwakanaka kwazvo. Kana paine kupindira kweruzha kubva kunze, anenge akabatanidzwa kune mitsetse miviri panguva imwe chete, uye magumo ekugamuchira anotarisira chete musiyano pakati pezviratidzo zviviri. Naizvozvo, iyo yekunze yakajairika modhi ruzha runogona kudzimwa zvachose. b. Inogona kunyatso kudzvanya EMI. Nechikonzero chimwe chete, nekuda kweiyo yakatarisana polarity yemasaini maviri, iwo emagetsi minda inovhenekerwa navo anogona kukanzura mumwe nemumwe kunze. Kubatana kwakasimba, ndiko kushomeka kwesimba remagetsi rinoburitswa kunyika yekunze. c. Iyo nguva yekumisikidza ndeyechokwadi. Nekuti shanduko yekuchinja kwechiratidzo chekusiyanisa iri pamharadzano yezviratidzo zviviri, kusiyana neyakajairwa-inogumira chiratidzo, icho chinoenderana nepamusoro uye yakaderera chikumbaridzo voltages kuona, haina kukanganiswa nemaitiro uye tembiricha, iyo inogona. kuderedza kukanganisa munguva. , Asi zvakare zvakanyanya kukodzera kune yakaderera-amplitude masaini maseketi. Iyo yazvino yakakurumbira LVDS (lowvoltagedifferentialsignaling) inoreva iyi diki amplitude yekusiyanisa chiratidzo tekinoroji.

Kune mainjiniya ePCB, chinonyanya kunetsa ndechekuti ungava sei nechokwadi chekuti izvi zvakanakira zvekusiyanisa wiring zvinogona kushandiswa zvizere mune chaiyo wiring. Zvichida chero ani zvake anga achibatana neLayout achanzwisisa zvinodikanwa zvekusiyanisa wiring, kureva, “kuenzana kureba uye kureba kwakaenzana”. Kureba kwakaenzana ndeyekuona kuti masaini maviri akasiyana anochengetedza polarities yakatarisana nguva dzese uye kuderedza yakajairika mode chikamu; daro rakaenzana rinonyanya kuve nechokwadi chekuti kusiyana kwezvipingamupinyi zvezviviri zvinopindirana uye kuderedza kuratidzwa. “Sepedyo sezvinobvira” dzimwe nguva chimwe chezvinodiwa zvekusiyanisa wiring. Asi iyi mitemo yese haishandiswe kuita zvemichina, uye mainjiniya mazhinji anoita seasati anzwisisa kukosha kweyekumhanya-mhanya kusiyanisa chiratidzo chekufambisa.

Izvi zvinotevera zvinotarisa pane akati wandei kusanzwisisana muPCB musiyano wechiratidzo dhizaini.

Kusanzwisisa 1: Zvinotendwa kuti chiratidzo chekusiyanisa hachidi ndege yepasi senzira yekudzoka, kana kuti misiyano yekusiyanisa inopa nzira yekudzoka kune mumwe nemumwe. Chikonzero chekusanzwisisana uku ndechekuti ivo vanovhiringika nepamusoro-soro zviitiko, kana iyo nzira yekumhanyisa-kumhanya chiratidzo chekufambisa haina kudzika zvakakwana. Zvinogona kuoneka kubva muchimiro chekugashira kwekupedzisira kweMufananidzo 1-8-15 kuti emitter mafungu e transistors Q3 neQ4 akaenzana uye akatarisana, uye iwo mafungu ari pasi akanyatso kudzima (I1 = 0), saka iyo differential circuit is Similar bounces uye mamwe masaini masaini angave aripo pane simba uye pasi ndege hadzina hanya. Kubviswa kwechikamu chekudzoka kwendege yepasi hakurevi kuti dunhu rekusiyanisa harishandisi ndege yereferensi senzira yekudzoka chiratidzo. Muchokwadi, mukuongororwa kwechiratidzo chekudzoka, iyo nzira yekusiyanisa wiring uye yakajairwa-inogumira wiring yakafanana, kureva kuti, masaini-akawanda masaini anogara achiyerera pamwe nechiuno nediki inductance, musiyano mukuru ndewekuti mukuwedzera kubatanidza pasi, mutsara wekusiyanisa unewo kubatanidza. Imhando ipi yekubatanidza yakasimba, iyo inova nzira huru yekudzoka. Mufananidzo 1-8-16 dhiyabhorosi dhiyagiramu yegeomagnetic munda kugovera kwemasaini-apera masaini uye akasiyana masaini.

MuPCB dhizaini yedunhu, kubatanidza pakati pekusiyanisa kunowanzo idiki, kazhinji inongoverengera gumi kusvika 10% yedhigirii rekubatanidza, uye zvimwe ndiko kubatanidza pasi, saka nzira huru yekudzoka yemusiyano wekusiyanisa ichiripo pasi. ndege . Apo ndege yepasi inorega, kubatanidza pakati pemitsara yakasiyana-siyana ichapa nzira huru yekudzoka munzvimbo iyo pasina ndege inotaridzirwa, sezvinoratidzwa mumufananidzo 20-1-8. Kunyangwe pesvedzero yekusaenderera mberi kweiyo ndege yereferenzi pane yekusiyanisa trace haina kukomba senge yakajairwa imwe-inopera trace, icharamba ichidzikisa kunaka kwechiratidzo chekusiyanisa uye kuwedzera EMI, iyo inofanirwa kudzivirirwa zvakanyanya sezvinobvira. . Vamwe vagadziri vanotenda kuti iyo ndege yereferensi pasi peiyo mutsauko trace inogona kubviswa kudzvanya mamwe masaini masaini masaini mukusiyanisa kutapurirana. Zvisinei, nzira iyi haidiwi mudzidziso. Nzira yekudzora sei impedance? Kusapa ivhu impedance loop yeyakajairika-modhi siginecha zvinozokonzeresa EMI radiation. Iyi nzira inokuvadza kupfuura kunaka.

Kusanzwisisa 2: Zvinotendwa kuti kuchengeta nzvimbo yakaenzana kwakakosha pane kufananidza kureba kwemutsara. Mune chaiyo PCB marongerwo, kazhinji hazvigoneke kusangana nezvinodiwa zvekusiyanisa dhizaini panguva imwe chete. Nekuda kwekuvapo kwekugovera kwepini, vias, uye nzvimbo yewaya, chinangwa chekuenzanisa kureba kwemutsara chinofanirwa kuwanikwa kuburikidza nekumonereka kwakaringana, asi mhedzisiro inofanirwa kuve yekuti dzimwe nzvimbo dzekusiyanisa peya hadzigone kuenderana. Chii chatinofanira kuita panguva ino? Isarudzo ipi? Tisati taita mhedziso, ngatitarisei kune inotevera simulation mhinduro.

Kubva pane zviri pamusoro mhedzisiro mhedzisiro, zvinogona kuoneka kuti mafungu eScheme 1 uye Scheme 2 anenge angofanana, kureva kuti, pesvedzero yakakonzerwa nekusaenzana nzvimbo ishoma. Mukuenzanisa, pesvedzero yehurefu hwemutsara kusapindirana pane nguva yakakura kwazvo. (Chirongwa 3). Kubva pakuongorora kwedzidziso, kunyangwe iyo isingaenderane nzvimbo inokonzeresa kusiyanisa impedance, nekuti kubatana pakati pekusiyanisa vaviri pachayo hakuna kukosha, iyo impedance shanduko yemhando zvakare idiki kwazvo, kazhinji mukati me10%, iyo inongofanana nekupfuura imwe chete. . Iyo fungidziro inokonzerwa negomba haizove nemhedzisiro yakakosha pakufambiswa kwechiratidzo. Kamwe urefu hwemutsara husingaenderane, mukuwedzera kune iyo nguva yekubvisa, zvakajairika mode zvikamu zvinounzwa muchiratidzo chekusiyanisa, izvo zvinoderedza kunaka kwechiratidzo uye kuwedzera EMI.

Zvinogona kutaurwa kuti mutemo unonyanya kukosha mukugadzirwa kwePCB mutsauko wekusiyanisa kureba kwemutsara, uye mimwe mitemo inogona kuchinjika kubatwa zvinoenderana nedhizaini zvinodiwa uye inoshanda mashandisirwo.

Kusanzwisisa 3: Funga kuti mutsauko wiring unofanirwa kunge uri padyo. Kuchengeta mutsauko uri padyo hapana chimwe kunze kwekuwedzera kubatana kwavo, izvo zvisingangogone kuvandudza kusadzivirirwa kune ruzha, asi zvakare kushandisa zvizere iyo yakatarisana polarity yegineti kumisa kukanganiswa kwemagetsi kune kunze kwenyika. Kunyange zvazvo nzira iyi inobatsira zvikuru muzviitiko zvakawanda, haisi yakakwana. Kana tikakwanisa kuve nechokwadi kuti dzakadzivirirwa zvizere kubva pakupindira kwekunze, saka hatidi kushandisa kubatanidza kwakasimba kuti tiwane kupesana-kupindira. Uye chinangwa chekudzvinyirira EMI. Tingaite sei kuti tive nechokwadi chekuzviparadzanisa nevamwe uye kudzivirira kwemavara akasiyana? Kuwedzera kupatsanura nemamwe masaini echiratidzo ndeimwe yenzira dzakanyanya kukosha. Iyo electromagnetic field energy inodzikira neskweya yechinhambwe. Kazhinji, kana mutsara wemutsara uchipfuura 4 nguva yehupamhi hwemutsara, kukanganisa pakati pavo hakuna simba zvakanyanya. Inogona kufuratirwa. Mukuwedzera, kuparadzaniswa nendege yepasi kunogonawo kutamba basa rakanaka rekudzivirira. Ichi chimiro chinowanzo shandiswa mune yakakwira-frequency (pamusoro pe10G) IC package PCB dhizaini. Iyo inonzi CPW chimiro, iyo inogona kuve nechokwadi chakasimba mutsauko impedance. Kudzora (2Z0), sezvakaratidzwa muMufananidzo 1-8-19.

Mutsara wakasiyana unogona zvakare kumhanya muakasiyana masaini akaturikidzana, asi nzira iyi haiwanzo kurudzirwa, nekuti misiyano yeimpedance uye vias inogadzirwa neakasiyana akaturikidzana inoparadza mhedzisiro yekusiyanisa modhi kutapurirana uye kuunza yakajairika modhi ruzha. Uye zvakare, kana maviri ari padyo akaturikidzana asina kubatanidzwa zvakasimba, zvinoderedza kugona kweiyo mutsauko wekutsvaga kuramba ruzha, asi kana iwe uchikwanisa kuchengetedza chinhambwe chakakodzera kubva kune yakatenderedza nhanho, crosstalk haisi dambudziko. Pazvizhinji frequencies (pazasi GHz), EMI haizove dambudziko rakakura. Ongororo dzakaratidza kuti kudzikisira kwesimba reradiated pachinhambwe che500 mils kubva kune yakasarudzika trace yasvika 60 dB pachinhambwe chemamita matatu, inokwana kusangana neFCC electromagnetic radiation standard, saka Mugadziri haafanire kunetsekawo. zvakawanda nezve kusapindirana kwemagetsi kunokonzerwa nekusakwana kusiyanisa mutsara wekubatanidza.

3. Mutsara wenyoka

Nyoka mutsetse imhando yenzira yekufambisa inowanzoshandiswa muRayout. Chinangwa chayo chikuru ndechekugadzirisa kunonoka kusangana nehurongwa hwekugadzirisa nguva. Mugadziri anofanira kutanga ave nekunzwisisa uku: mutsara wenyoka uchaparadza mhando yechiratidzo, shandura kunonoka kwekufambisa, uye edza kudzivisa kuishandisa kana wiring. Zvisinei, mukugadzirwa kwechokwadi, kuitira kuti ive nechokwadi chokuti chiratidzo chine nguva yakakwana yekubata, kana kuderedza nguva yekugadzirisa pakati peboka rimwe chete rezviratidzo, zvinowanzodiwa kuvhuvhuta nemaune waya.

Saka, mutsara wenyoka une mhedzisiro yei pakufambiswa kwemasaini? Chii chandinofanira kuteerera kana wiring? Maparamendi maviri akanyanya kuomesesa ndeaya anoenderana kureba kwekubatanidza (Lp) uye chinhambwe chekubatanidza (S), sezvakaratidzwa mumufananidzo 1-8-21. Zviripachena, kana chiratidzo chikafambiswa pane iyo nyoka trace, iyo inofananidzwa mitsetse zvikamu zvichabatanidzwa mune yekusiyanisa modhi. Iyo diki iyo S uye yakakura iyo Lp, iyo yakakura dhigirii yekubatanidza. Inogona kukonzera kunonoka kwekutapurirana kudzikiswa, uye mhando yechiratidzo inodzikiswa zvakanyanya nekuda kwecrosstalk. Iyo meshini inogona kureva kuongororwa kweakajairwa modhi uye musiyano modhi crosstalk muChitsauko 3.

Aya anotevera mamwe mazano eLayout mainjiniya kana achibata nemitsara yenyoka:

1. Edza kuwedzera chinhambwe (S) chezvikamu zvemitsara inofananidzwa, inodarika 3H, H inoreva chinhambwe kubva pachiratidzo chechiratidzo kuenda kundege yereferensi. Mukutaura kwevasina basa, ndiko kutenderera kwakakombama. Chero bedzi S yakakura zvakakwana, iyo mutual coupling mhedzisiro inogona kudzivirirwa zvachose. 2. Deredza kureba kwekubatanidza Lp. Kana iyo yakapetwa kaviri Lp kunonoka kunosvika kana kudarika chiratidzo chekusimuka nguva, iyo crosstalk inogadzirwa inosvika pakuzara. 3. Kunonoka kwekufambisa kwechiratidzo kunokonzerwa nemutsara wenyoka weStrip-Line kana Embedded Micro-strip ishoma pane iyo yeMicro-strip. Mune dzidziso, iyo stripline haizokanganisa mwero wekutapurirana nekuda kwekusiyanisa mode crosstalk. 4. Kune mitsetse yechiratidzo chepamusoro-soro uye avo vane zvinodiwa zvakasimba zvenguva, edza kusashandisa mitsara yenyoka, kunyanya munzvimbo duku. 5. Iwe unogona kazhinji kushandisa mitsara yenyoka chero ipi zvayo, yakadai seC chimiro muMufananidzo 1-8-20, iyo inogona kubudirira kuderedza kuwirirana. 6. Mukugadzirwa kwePCB yakakwirira-yepamusoro, mutsara wenyoka hauna izvo zvinonzi kusefa kana kuti anti-interference kukwanisa, uye inogona kungoderedza zviratidzo zvehutano, saka inongoshandiswa pakufananidza nguva uye haina chimwe chinangwa. 7. Dzimwe nguva unogona kufunga nezve spiral routing yekumonereka. Simulation inoratidza kuti mhedzisiro yacho iri nani pane yakajairwa serpentine routing.