Kufananidza Impedance muHigh-Speed ​​​​PCB Design

Munyaya yekugadzirwa kwePCB inomhanya zvikuru , kufananidza impedance kunoita basa guru mukuona kuti chiratidzo chinotumirwa zvakanaka pakati pemutyairi nezvikamu zvinogamuchira. Inzira yakakosha ine chinangwa chekubvisa kuratidzwa kwechiratidzo uye kuchengetedza simba rakakwana kusvika parinogamuchira. Kunyange zvazvo pfungwa yekuchengetedza impedance ye50 Ohm yePCB traces ichiwanzotaurwa, kuomarara kwekubatanidza impedance kunova pachena kana tichibata nekubatana pakati pemapairi akasiyana. Ngatinyatsoongororai maitiro aya akakosha uye tiongorore nzira dzekuwana kufananidza impedance mune zvese zviitiko zvechiratidzo chimwe chete uye chekusiyana.

Impedance Matching yeIngle-inopera Signals

Impedance yekuenzanisa kwemasaini-apera masaini chinhu chakakosha chepamusoro-kumhanya PCB dhizaini, sezvo ichikanganisa zvakananga kutendeseka kwechiratidzo uye kutapurirana. Zvinhu zvakasiyana, zvinosanganisira trace geometry, logic mhuri, uye coupling, zvinopesvedzera impedance mismatches mumasaini-apera masaini. Vagadziri vanofanirwa kutarisisa zvinhu izvi pavanenge vachigadzira zviteshi kuti ive nechokwadi chekuti impedance inoenderana nepakati pechiratidzo bandwidth.

Chimwe chinhu chakakosha pakuwana impedance kuenzanisa kunzwisisa kupinza uye kubuda impedance spectra yemasekete akabatanidzwa (ICs) anobatanidzwa mukugadzira. Vagadziri veIC vanowanzopa ruzivo rwakakosha maererano nepini-package lead inductance, kugona kwekuisa, uye yakaenzana yekupinza kuramba. Ruzivo urwu runoshanda seyakakosha sosi yevagadziri, ichipa manzwisisiro mukati meiyo impedance maitiro eICs uye kutungamira kuita kweyakajairwa impedance yekufananidza zvirongwa.

Nekuongorora iyo yekupinda uye inoburitsa impedance spectra inopihwa nevagadziri veIC, vagadziri vanogona kuwana kunzwisisa kwakadzama kwezvinodikanwa zve impedance kune yavo chaiyo application. Ruzivo urwu runogonesa vagadziri kusarudza nzira dzakakodzera dzekumisa uye kukwidziridza trace geometries kuti vawane yakakwana impedance yekufananidza. Pamusoro pezvo, kunzwisisa iyo impedance hunhu hweICs inobvumira vagadziri kuti vafungidzire zvingangoita impedance mismatches uye kuita matanho ekugadzirisa pakutanga kwemaitiro ekugadzira.

Muchidimbu, kufananidza impedance yezviratidzo zvine magumo rimwe chete kunoda kunyatsotarisisa zvakadzama uye kunzwisisa kwakakwana kwehunhu hwe impedance hwemaIC. Nekushandisa ruzivo rwunopihwa nevagadziri veIC uye kushandisa zvirongwa zvekuenzanisa impedance zvakajairwa, vagadziri vanogona kuve nechokwadi chekuti kufananidza impedance kwakakodzera mubandwidth yechiratidzo, zvichikonzera kuvandudzwa kwekuvimbika kwechiratidzo uye kushanda zvakanaka kwekutumira mumagadzirirwo ePCB anomhanya zvakanyanya.

Impedance Matching Schemes yeSingle-ended Transmission Lines

Mune yakakwirira-kumhanya PCB dhizaini, kuwana impedance yekufananidza kune imwe-inopera mitsara yekufambisa kwakakosha kudzikisa zviratidzo zvechiratidzo uye kuve nechokwadi chekufambisa kwesimba kunoenderana nemutsetse wekutumira. Akawanda akajairwa impedance yekufananidza zvirongwa anowanzo shandiswa kugadzirisa impedance mismatches uye kukwidziridza kutendeka kwechiratidzo. Zvirongwa izvi zvinosanganisira kugumiswa kwakatevedzana, kugumiswa kwakafanana, uye kugumiswa nevaparidzi vanopikisa.

1. Series Kugumiswa: Series kugumiswa kunosanganisira kuisa yekumisa resistor munhevedzano netambo yekutumira pamagumo ekupedzisira. Iko kukosha kwekumisa resistor inosarudzwa kuti ienderane nehunhu impedance yemutsetse wekutumira. Ichi chirongwa chinonyatso kudzikisa zviratidzo zvechiratidzo nekumisa tambo yekutapurirana pane yayo hunhu impedance, kudzivirira chiratidzo overshoot uye undershoot kumagumo anogamuchira.
2. Parallel Kugumiswa: Parallel kumisa, kunozivikanwawo se shunt kumisa, kunosanganisira kuisa yekumisa resistor inoenderana nekuremerwa kwemutoro kumagumo ekugamuchira. Iyo yekumisa resistor kukosha inosarudzwa kuti ienderane nehunhu impedance yemutsetse wekutumira. Parallel kumisa kunopa imwe nzira yekumisa nhevedzano uye inonyanya kushanda mumamiriro ezvinhu apo kugumiswa kwenhevedzano kungasaite kana kudiwa.
3. Kugumiswa neResistive Dividers: Kugumiswa nevaparidzi vanopikisa kunosanganisira kushandisa musanganiswa weakatevedzana uye akafanana kumisa maresitorendi kuti uwane impedance inoenderana. Ichi chirongwa chinowanzo shandiswa mumashandisirwo apo iyo hunhu impedance yemutsetse wekutumira isingaenderane nekuremerwa kwemutoro. Nekusarudza zvakakodzera kukosha kweakatevedzana uye akafanana kumisa resistors, vagadziri vanogona kuwana yakaringana impedance yekufananidza uye kuderedza zviratidzo zvechiratidzo.

Differential Signaling uye Impedance Matching

Kusaina kusaina inzira yakajairika inoshandiswa munzvimbo dzakasiyana-siyana dzekumhanya-mhanya nekuda kwekugona kwayo kupa yakanyanya ruzha kusadzivirirwa uye yakakwirira data data zvichienzaniswa nekusaina-kunopera. Yakasiyana miyero uye mapuroteni anoraira chaiwo impedance zvinodiwa kune akasiyana maviri maviri, imwe neimwe ichiunza yakasarudzika matambudziko mukufananidza impedance. Pazasi pane mamwe anocherekedza akakwira-kumhanya mutsauko masiginecha zviyero pamwe neavo impedance maitiro:

1. LVDS (Yakaderera-Voltage Differential Signaling):
   • LVDS interfaces inowanzoisa yakakwira yekupinza impedance. Kuti uenzanise impedance yeanogamuchira kune yega yega ye50-ohm inoteedzera mune inosiyanisa maviri, parallel resistor inoshandiswa kune anogamuchira. Kubatanidza DC, kugumiswa kaviri ne100-ohm resistor pamativi akasiyana-siyana anowanzo shandiswa kuenzanisa mutsauko wekukanganisa kwevaviri.
2. CML (Yazvino Mode Logic):
   • CML interfaces inotsanangura kupinza uye kuburitsa impedance ye50 ohms, inonongedzwa kune imwechete-inogumira impedance yega yega trace mune inosiyanisa peya. Mamwe machipisi eCML anogona kushaya mapikisi ekumisa ekuisa, zvichidikanwa kushandiswa kwekudhonza-kumusoro uye kudonhedza-pasi resistors kuti aenderane nedanho rekuisa kune Vdd level pane chip.
3. PECL (Pseudo-Emitter Coupled Logic):
   • PECL interfaces inoratidzira ine 100-ohm mutsauko impedance uye 50-ohm imwe-yapera impedance. Nekuda kweiyo yakaderera impedance yePECL zvinobuda (~ 5 ohms), kudhonza-kumusoro / kudhonza-pasi resistors kwakakosha pakufananidza kwe impedance.
4. HSTL (High Speed ​​Transceiver Logic):
   • HSTL inombundira makirasi mana ekusaina pakati peCMOS neBiCMOS zvishandiso, imwe neimwe ichida nzira dzakasiyana dzekumisa kuti uwane impedance yekufananidza.
5. PCIe (Peripheral Component Interconnect Express):
   • PCIe mazinga anotsanangura mutsauko impedance zvinodiwa, nePCIe Gen1 ine 100-ohm mutsauko impedance uye Gen2 uye yepamusoro iine 85-ohm musiyano we impedance.
6. Ethernet:
   • Mitsetse yeEthernet inoshandisa mapeya akasiyana-siyana ane 100-ohm differential impedance uye 50-ohm single-ended impedance.
7. USB (Universal Serial Bus):
   • USB mainterfaces ane hunhu hunhu hwe50 ohms, iine musiyano we impedance inofananidzwa yakaiswa pa90 ohms, ichienderana nekusiyana kwekukanganisa kwetambo ye USB.

Izvo zvakakosha kuti uzive kuti kune mamwe akakwira-kumhanya mainterface anoshandiswa mumakomputa peripherals, akadai seLVPECL (yakaderera-voltage PECL), iyo ine yavo impedance maitiro. Kana uchibatanidza pakati peakasiyana akakwira-kumhanya kusiyanisa masiginecha zviyero, network yekudhonza-kumusoro uye yekudhonza-pasi resistors inogona kushandiswa kuve nechokwadi chekuenderana.

Mabatiro Ekubatana muMaviri Akasiyana Kunokanganisa Impedance Matching

Kunzwisisa kuti kubatana mumaviri akasiyana kunokanganisa sei impedance kuenzanisa kwakakosha kuti uwane yakakwana chiratidzo chekuvimbika mune yakakwirira-kumhanya PCB dhizaini. Mukusiyanisa kusaina, uko masaini anofambiswa seanopindirana pairi, iyo impedance hunhu hwematanho ega ega anokonzerwa nekuwirirana capacitance uye mutual inductance pakati pavo. Kudyidzana uku kunoguma kune maviri akasiyana impedance maitiro: hunhu impedance (Z0) uye odd-mode impedance.

1. Characteristic Impedance (Z0):
   • Characteristic impedance inoreva kuvharika kwechiratidzo chimwe chete kana chaparadzaniswa nemamwe mavara uye chichifambiswa nechiratidzo. Izvo zvinoenderana nekutsvaga geometry, dielectric kugadzika kweiyo substrate zvinhu, uye chinhambwe kuenda kundege yereferensi (ndege yepasi).
   • Kana iyo chete trace uye ndege yepasi iripo paPCB, iyo trace impedance yakaenzana nehunhu impedance (Z0).
2. Odd-Mode Impedance:
   • Odd-mode impedance inomuka apo mitezo miviri muvaviri vakasiyana inounzwa padhuze, zvichikonzera kuwirirana uye kuwirirana pakati pavo.
   • Sezvo maronda achifambiswa zvakasiyana, iyo mutual capacitance uye inductance inoshandura iyo impedance maitiro ega ega trace, zvichitungamira kune isinganzwisisike-mode impedance iyo yakaderera pane hunhu impedance.

Iyo yekusiyanisa impedance mune mbiri inongori kaviri kukosha kweiyo odd-mode impedance (Z(diff) = 2Z(odd)). Nekudaro, zvakakosha kuti uzive kuti dhizaini yekusiyanisa impedance yakaenzana nekaviri hunhu impedance (Z0) inogona kusakonzeresa yakakwana impedance yekufananidza yeakakwira-kumhanya masaini.

Huyero hwehunhu impedance kune isinganzwisisike-modhi impedance zvinoenderana nezvinhu zvakaita seyekuteedzera nzvimbo uye substrate kureba. Makumbo ma substrates uye kuswedera pedyo kwekutsvaga nzvimbo kunokonzeresa kutsauka kukuru pakati pehunhu neodd-mode impedance.

Mune mapeya akasiyana, impedance yekufananidza inowanikwa nekugadzira imwe neimwe trace ine hunhu impedance yakati kurei kupfuura 50 Ohms, uku ichiona kuti hupamhi hwevaviri hunoisa iyo mutsauko impedance kune chaizvo zana Ohms. Iyi nzira yekugadzira inoisa iyo isinganzwisisike-modhi impedance ku100 Ohms, ichifambisa inoshanda impedance kuenzanisa.

Mukuita masimulation uye zviyero, kumisa zvipikisi zvinoshandiswa kumisa iyo mutsauko wekuisa kune yakatsanangurwa mutsauko impedance, inova kaviri iyo isinganzwisisike-modhi impedance. Izvi zvinodzivirira kuratidzwa kwechiratidzo kushoma uye kuchengetedza chiratidzo chekuvimbika.

5 Unofanira Kuziva Mitemo kuti uwane impedance control muPCB

Impedance control in printed circuit board (PCB) dhizaini yave kunyanya kunetsa nekuuya kwemaseketi emagetsi epamusoro anotaridzwa neminiaturization, masaini akakwira-frequency, high componety density, uye mashandiro akaomarara. Iyo PCB, iri hwaro hwechero dunhu remagetsi, yakashanduka kuti igadzirise izvi zvakaomarara uku ichivimbisa kutendeseka kwechiratidzo, izvo zvakakosha pakuparidzirwa kwechiratidzo pasina kukanganisa pasi pemamiriro ekushanda.

Sezvo masaini paPCB anoteedzera kuita senge mitsara yekutapurirana ine chaiyo impedance kukosha pane imwe neimwe nzvimbo parutivi rwekuteedzera, kuchengetedza inopindirana impedance kwakakosha. Chero mutsauko weimpedance padivi pekutsvaga unogona kutungamira kune chiratidzo chekuratidzira, uko chikamu chesimba rechiratidzo chinoratidzwa kumashure nekuda kwekukanganisa kusawirirana. Kuti zvigadzirise izvi, vagadziri vanofanirwa kuve nechokwadi chekusamira, izvo zvinoenderana nezvinhu zvakasiyana zvinosanganisira kuteedzera hupamhi, kuteedzera ukobvu, substrate dielectric nguva dzose (Ɛr), substrate ukobvu, uye kuteedzera marongero paPCB. Common impedance values ​​dzinowanzo siyana pakati pe25 ne120 Ω.

Impedance Measurement

Kusimbisa magadzirirwo ePCB uye kuona kukosha kweiyo impedance pamwe nemitsara yekufambisa, vagadziri vanowanzo shandisa Time Domain Reflectometry (TDR) matekiniki ekuyera. TDR inoshandisa pulse jenareta uye oscilloscope kutumira kukurumidza kupuruzira kuburikidza nemutsetse wekutumira. Kana paine kusaenderera mberi kwe impedance, chikamu chekupuruzira chinoratidzwa kumashure. Nekuyera nguva yakatorwa kuti chiratidzo chinoratidzwa chidzoke kune oscilloscope uye kuenzanisa amplitude yayo neyekutanga pulse, vagadziri vanogona kuona nzvimbo uye ukuru hwekusiyana kwe impedance pamutsara wekutapurirana. TDR inopa manzwisisiro mukusiyana kwe impedance pane yakafara spectrum yema frequency.

Design Mitemo

1. Microstrip uye Stripline Parameters: Microstrip traces, inowanzoshandiswa pazvikamu zvekunze zvePCBs, inoratidza yakakwirira hunhu impedance inokonzerwa nezvinhu zvakaita se dielectric constant, trace wide, trace thickness, uye substrate ukobvu. Kugadzirisa aya ma paramita panguva yekugadzira nekugadzira kwakakosha kuchengetedza yaidiwa impedance hunhu. Striplines, inosanganisira conductive strip pakati pendege mbiri dzepasi, zvakafanana zvinoenderana nehupamhi, substrate ukobvu, uye dielectric zvivakwa zve impedance control.
2. Sarudzo Yechiratidzo: Vagadziri vanofanirwa kutsanangura zvakajeka kuti ndeapi masaini anoda impedance kudzora zvichibva pane chikamu chedatas, izvo zvinowanzopa impedance kukosha kurudziro. Zvikwangwani zvakaita sewachi kana mitsara yedata yeDDR ndangariro, odhiyo/vhidhiyo masaini, gigabit Ethernet, kana RF masaini anowanzoda impedance control.
3. Trace Spacing: Yakakwana nzvimbo pakati pematanho, kunyanya ayo ane inodzorwa impedance, yakakosha kudzikisa crosstalk. Kushandisa nzvimbo shoma ye“2W” (kana kuti ingangoita “3W”) apo “W” inomiririra hupamhi hwekutsvagira kunobatsira kudzikisira crosstalk. Kune masiginecha akakwira-frequency, wedzera nzvimbo kusvika ku "5W" kuderedza kupindira.
4. Vias uye Bypass Capacitors: Dzivisa kuisa zvinoriumba uye vias pakati pemaviri masaini masaini sezvo vanogona kugadzira impedance discontinuities. Symmetrical positioning ye serial coupling capacitors inobatsira kudzikisira kusaenderera kwechiratidzo.
5. Trace Length Matching: Kuenzanisa kureba kwekutevera kunovimbisa kuti masaini anosvika panguva imwe chete kwaainoenda, yakakosha kumapoka-anomhanya-mhanya senge DDR memory data mitsara kana mapeya ezviratidzo zvakasiyana. Matekinoroji akaita sekuisa nyoka mumapfupi anobatsira kuenzana kureba uye kuderedza impedance discontinuities.

Kuomerera kune iyi dhizaini mitemo inovimbisa inoshanda impedance kudzora muPCB dhizaini, kufambisa yakavimbika chiratidzo kutapurirana uye kuchengetedza chiratidzo chekutendeseka mukuwedzera kuoma kwemagetsi maseketi.

PCB Substrate Chinyorwa Sarudzo uye Stackup Dhizaini

Kusarudza zvinhu zve substrate zvakakodzera uye kugadzira stackup matanho akakosha mukugadzira PCB kuderedza migumisiro yeparasite uye kuve nechokwadi chekuti impedance inogara iripo mudunhu rese. Kugadzikana kwe dielectric kwezvinhu zve substrate kunokanganisa zvakananga geometry inodiwa kuti uwane impedance chaiyo ye transmission line uye kunokanganisa impedance ye network yekupa simba. Pamusoro pezvo, kuvapo kwema planes ari pasi pe conductors kunokanganisa loop impedance, iyo inogona kukanganisa mukana we circuit kukanganiswa ne electromagnetic interference ( EMI ).

Impedans Matching Networks

Iyo stackup dhizaini zvakare inokanganisa kupisa kwekupisa, nzira yekufambisa, uye chiratidzo chekuvimbika. Nekubatanidza iyo yakakodzera substrate zvinhu neiyo stackup dhizaini, kurasikirwa kwechiratidzo kunogona kuderedzwa, uye impedance kuenderana kunochengetwa kudunhu rese. Consistent impedance kuenzanisa kwakakosha kudzivirira masaini kuratidza sechiratidzo chekuchinja kuenda kune kutapurirana mutsara maitiro. Kuve nechokwadi chekuti mitsara yekutapurirana, vatyairi, uye vanogamuchira vane inopindirana impedance mukati medunhu kwakakosha kuchengetedza chiratidzo chekuvimbika.

Via Impedance

Vias inosuma parasitic mhedzisiro yakafanana neiyo ye substrate zvinhu, kusanganisira inductance, capacitance, uye mutual coupling. Vias inoita senge impedance discontinuities mumitsara yekutapurirana, uye kushandiswa kwavo kunofanirwa kudzikiswa mumaseketi ekumhanya uye akakwira-frequency kudzivirira kubatana kweruzha uye kusaina nyaya dzekuvimbika.

Kuyera uye Kuongorora Impedance

Impedance yekuyera matekiniki anosanganisira majenareta echiratidzo, oscilloscopes, uye impedance metres kana analyzer kuti vaongorore amplitude, chikamu chekuchinja, uye frequency mhinduro. Maturusi ekufananidza, akadai seSPICE-based simulators, anobvumira kuongororwa kwe impedance panguva yechikamu chekugadzira. AC frequency sweeps uye Bode plots inogona kuona iyo impedance yese yedunhu bhuroka nemhedzisiro yayo pachiratidzo chehukuru uye chikamu. Nonlinear maseketi anoda mamwe ongororo yepamusoro, senge DC sweeps, diki-signal ongororo, uye harmonic chiyero kuongororwa, kuti unzwisise impedance maitiro pasi pemamiriro akasiyana ekushanda.

Kuwana Impedance Matching muHigh-Speed ​​PCB Dhizaini

Impedance kuenzanisa chinhu chakakosha chepamusoro-kumhanya PCB dhizaini, kuve nechokwadi chekuvimbika kwechiratidzo uye kuderedza kuratidzwa pamwe nemitsara yekufambisa. Kunyatsodzorwa impedance inoreva kuti iyo impedance yekuteedzera inoramba ichigara panzvimbo yega yega munzira paPCB, zvisinei nekuchinja mumatanho kana nzira. Kuwana impedance kuenzanisa kunoda kunyatsotariswa kwemaitiro ekugadzira, kusarudzwa kwezvinhu, uye nzira dzekugadzira. Mugwaro rino rakazara, isu tichaongorora mukati mezvakasiyana zvinhu zvinosanganisirwa mukuwana impedance yekufananidza mune yakakwirira-kumhanya PCB dhizaini.

Peji rino ndiro gwara guru rekusarudza kufananidza impedance. Kana muverengi achida zvinorehwa nepfungwa yekutanga, shandisa zvinorehwa nekufananidza impedance ; kuti uongorore kuburitswa kwemhinduro kuenda kukugadzirwa, zvibatanidze nePCB dhizaini yekukurumidza yekugadzira uye Highleap's controlled impedance PCB.

Kukosha kweImpedans Matching

Impedance yekuenzanisa inoita basa rakakosha mukumhanya-mhanya PCB dhizaini kuve nechokwadi chekufambisa kwemasaini uye kuderedza kukanganiswa kwechiratidzo. Kusapindirana impedance pamwe nemitsara yekutapurirana kunogona kutungamira kune masaini kuratidza, impedance mismatches, uye EMI nyaya, pakupedzisira zvichikanganisa kuita kwese uye kuvimbika kweiyo yemagetsi system. Nekuwana impedance kuenzanisa, vagadziri vanogona kukwidziridza kutendeseka kwechiratidzo, kuderedza kurasikirwa kwechiratidzo, uye kuwedzera kushanda kwePCB.

Dhizaini Yemaitiro eImpedance Matching

Yakati wandei yakakosha dhizaini maitiro anofanirwa kutariswa kuti uwane impedance inoenderana mune yakakwirira-kumhanya PCB dhizaini:

1. Inodzorwa Impedance PCB Zvishandiso: Kusarudza iyo chaiyo laminate zvinhu kwakakosha kuti uwane inopindirana impedance muPCB yese. Zvishandiso zvine yakaderera dielectric constants (Dk) uye yakaderera kurasikirwa tangents inosarudzwa kune yakakwirira-kumhanya maapplication kudzikisa kukanganiswa kwechiratidzo uye chikamu jitter. Semuenzaniso, Isola FR408 inopa inowirirana dielectric nguva dzose ye3.7, ichiita kuti ive sarudzo yakanakisa yeakakwira-kumhanya PCB magadzirirwo.
2. Kurasika Tangent uye Kurasika Kwechiratidzo: Iyo yekurasikirwa tangent kana disipation factor yelaminate material inosarudza kurasikirwa kwechiratidzo sezvo chiratidzo chinopararira pasi mutsetse wekutumira. Kune epamusoro-frequency dhizaini, kusarudza chinhu chine yakaderera kurasikirwa tangent kwakakosha kudzikisa kudzika kwechiratidzo uye kuchengetedza chiratidzo chekuvimbika.
3. Dielectric Spacing uye PCB Kugadzirwa: Yakakodzera dielectric spacing pakati pemhangura yemhangura uye iyo laminate substrate yakakosha kuti iwane kuenderana kushanda kwemagetsi muPCB. Kutevedzera IPC4101 giredhi yevare laminate inovimbisa kugadzirwa kwemhando yepamusoro uye kuita kwakavimbika.
4. Fiberglass Weave Pattern: Iyo fiberglass weave pattern ye laminate material inokanganisa kufanana kwe dielectric constant muPCB yese. Kusarudza laminate ine yakaomesesa weave pateni inoita kuti iwedzere kuenderana dielectric, ichideredza trace impedance mutsauko uye kuparadzira skews, kunyanya pakakwirira.

Kusarudzwa kwezvinhu uye Kutsanangurwa

Kunyatsosarudzwa kusarudzwa uye kutsanangurwa kweiyo laminate zvinhu kwakakosha kuti uwane impedance yekufananidza mune yakakwirira-kumhanya PCB dhizaini. Mafungiro akadai se dielectric kugara, kurasikirwa tangent, uye fiberglass weave pateni inofanirwa kuongororwa kuti ive nechokwadi chekuita kwechiratidzo chechokwadi uye kuvimbika. Pamusoro pezvo, kudoma zvinhu zvakasarudzwa mumanotsi ekugadzira kunobatsira kuchengetedza kuwirirana pamabhechi ebhodhi uye kuve nechokwadi chekutevedzera dhizaini yedhizaini.

Simulation uye Analysis Zvishandiso

Maturusi ekuedzesera uye ekuongorora, akadai seSPICE-based simulators uye field solvers, akakosha pakuona trace impedance, kuongorora masignal maitiro, uye kuona kutevedza zvinodiwa nedhizaini. Zvishandiso izvi zvinobvumira vagadziri kufanotaura uye kukwidziridza impedance kuenzanisa, kuona zvinogona kuitika chiratidzo chekuvimbika, uye kunatsa dhizaini yePCB kuti iite zvakakwana.

Kuwana impedance yekufananidza mune yakakwira-kumhanya PCB dhizaini kwakakosha kuti uve nechokwadi chekufambisa kwemasaini, kudzikisira kukanganiswa kwechiratidzo, uye kugadzirisa mashandiro ehurongwa hwese. Nekunyatsofunga nezve magadzirirwo edhizaini, kusarudza zvinhu zvakakodzera, uye kushandisa maturusi ekuenzanisa, vagadziri vanogona kubudirira kuwana impedance yekufananidza uye kuwedzera chiratidzo chechiratidzo chePCB yavo magadzirirwo. Nekunyatsotarisisa kune zvakadzama uye kuomerera kune akanakisa maitiro, vagadziri vanogona kubudirira kukunda matambudziko ane chekuita ne impedance uye kuendesa yakakwirira-inoshanda emagetsi masisitimu.

Yekuwedzera Dhizaini Mafungiro eImpedance Control

Pamusoro peiyo nzira dzepakati dzekudzora impedance dzakambotaurwa, kune akati wandei mamwe magadzirirwo ekufunga anogona kuwedzera kutendeseka kwechiratidzo uye impedance yekufananidza muakadhindwa wedunhu bhodhi (PCB) madhizaini:

Kugadzirisa Kureba kweTrace : Kuchengeta mitsetse mipfupi sezvinobvira kunobatsira kuderedza kunonoka kwekupararira kwechiratidzo uye kuderedza njodzi yekuora kwechiratidzo. Kana kureba kwenguva refu kwetrace kusingadzivisike, magumo anofanirwa kushandiswa kuderedza kuratidzwa uye kuchengetedza kusimba kwechiratidzo.

Dzivisa Kuisa Zvidimbu Zvenzira : Zvidimbu zvenzira zvinogona kuunza kuratidzwa uye kuderedza kunaka kwechiratidzo. Mainjiniya anofanira kuedza kuderedza kana kubvisa zvinhu izvi mumagadzirirwo ePCB kuti ave nechokwadi chekuti kupindirana kwakafanana munzira dzese dzechiratidzo.

Kuronga Mapairi Akaenzana Nehurefu Hwakaenzana : Pakuronga mapairi akasiyana, kuchengetedza hurefu hwakaenzana hwemapairi echiratidzo kwakakosha kuchengetedza kusimba kwechiratidzo uye kudzivirira kutsveyama pakati pezviratidzo zvakanaka nezvakaipa.

Kuboorera Musana : Mumagadzirirwo emusana akakora uko zviratidzo zvekuchinja pakati pezvikamu, kuboorera kumashure kunogona kushandiswa kubvisa zvikamu zvisina kushandiswa zvemavias kana ma press-fit connectors, anozivikanwa se stubs, izvo zvinogona kukonzera kuratidzwa uye kusagadzikana kwe impedance.

Kusarudza Kupedza Pamusoro : Funga nezvekushandisa sirivha yekunyudza senzira yekupedzisa pamusoro pachinzvimbo cheENIG (Electroless Nickel Immersion Gold) yemagadzirirwo ekumhanya kukuru. Sirivha yekunyudza inopa kurasikirwa kwakaderera kwekupinza uye kushanda kuri nani pamafrequencies akakwira zvichienzaniswa neENIG, izvo zvinogona kubatsira pakuwana kuvimbika kwakakwana kwechiratidzo.

Kugadzirisa Saizi yeAntipad : Deredza saizi yemaantipad ari muzvikamu zveplane kuti uderedze maburi asina basa muplane uye uvandudze kuenderera mberi kweplane. Maantipad madiki anobatsira kuchena kwechiratidzo uye nzira yekudzoka, zvichiwedzera kusimba kwechiratidzo chose.

Taura Ukobvu hweMasiki yeSolder : Ukobvu hwemasiki yesolder hunogona kukanganisa kupararira kwechiratidzo uye hunofanira kutsanangurwa nguva dzose kudzivirira kusiyana kwehunhu hwe dielectric hunogona kukanganisa mashandiro echiratidzo.

Kuenzanisa uye Kuongorora Mushure meKugadzira : Kuita ongororo yekuenzanisa mushure mekugadzira uye kuvimbika kwechiratidzo uchishandisa maturusi akakosha kunogona kubatsira kuona nekugadzirisa matambudziko angangoitika ane chekuita ne impedance PCB isati yagadzirwa. Kuisa mari mukuenzanisa nekuongorora pakutanga kwekugadzira kunogona kudzivirira kugadziriswa kunodhura uye kuve nechokwadi chekuti kuvimbika kwechiratidzo kwakakodzera.

Nekubatanidza aya ekuwedzera magadzirirwo ekufunga padivi pechinyakare impedance control matekiniki, mainjiniya anogona kukwidziridza PCB dhizaini yekusimudzira chiratidzo chekuvimbika uye yakavimbika yekumhanya-mhanya kuita.

Ko CAM Injiniya Dzinodzora Impedance?

CAM (Computer-Aided Manufacturing) mainjiniya anoita basa rakakosha mukudzora impedance mumadhizaini akadhindwa edunhu (PCB). Ivo vanoshandisa nzira dzakasiyana siyana uye nzira dzekuona kuti izvo zvinodikanwa zveimpedance zvinotsanangurwa nemainjiniya ekugadzira zvinosangana panguva yekugadzira. Heano maitiro eCAM mainjiniya anodzora impedance:

1. Dhizaini Ongororo uye Ongororo: Injiniya dzeCAM dzinoita ongororo yakadzama yePCB dhizaini mafaera kuti anzwisise zvinodikanwa zveimpedance zvinotsanangurwa nevanogadzira mainjiniya. Ivo vanoongorora iyo stackup dhizaini, kuteedzera geometries, uye zvivakwa zvezvinhu kuti vaone iyo impedance hunhu hunodiwa kune akasiyana masaini trace.
2. Stackup Design Optimization: CAM mainjiniya anokwirisa iyo PCB stackup dhizaini kuti iwane inodiwa impedance kukosha kwechiratidzo chechiratidzo. Ivo vanosarudza yakakodzera laminate zvinhu zvine chaiwo dielectric constants uye ukobvu kudzora impedance zvinobudirira. Nekugadzirisa dhizaini yekumisikidza uye dielectric spacing, vanogona kukwenenzvera hunhu hweiyo impedance yePCB.
3. Tevera Upamhi uye Kugadziriswa Kwenzvimbo: CAM mainjiniya gadzirisa hupamhi uye nzvimbo yechiratidzo chechiratidzo kuti uwane iyo inotarirwa impedance kukosha. Ivo vanoshandisa akasarudzika maturusi esoftware kuverenga iyo impedance yeakasiyana trace geometri uye kugadzirisa sezvinodiwa kuti isangane nezvinodiwa zvekugadzira.
4. Controlled Etching Process: Munguva yePCB yekugadzira maitiro, mainjiniya eCAM vanova nechokwadi chekuti etching maitiro anodzorwa nekungwarira kuchengetedza inodiwa trace geometries uye zviyero. Chaiyo etching matekiniki anobatsira kuwana inopindirana impedance hunhu muPCB yese.
5. Kudzora Kwemhando uye Kuedzwa: Injiniya dzeCAM dzinoita macheki ekutonga kwemhando uye maitiro ekuyedza kuona kuti maPCB akagadzirwa anosangana nezvinodiwa zve impedance. Ivo vanoshandisa impedance yekuyedza michina uye yekuyera matekiniki kusimbisa iyo impedance kukosha kwechiratidzo chechiratidzo uye kuve nechokwadi chekutevedzera dhizaini yekugadzira.
6. Zvinyorwa uye Kushuma: Chekupedzisira, mainjiniya eCAM anonyora iyo impedance control process uye inopa yakadzama mishumo kune vanogadzira mainjiniya. Ivo vanosimbisa chero kutsauka kubva kune yakatsanangurwa impedance kukosha uye vakurudzira zviito zvekugadzirisa kana zvichidikanwa kuti ive nechokwadi chekuti maPCB ekupedzisira anosangana nezvinodiwa maitiro ekuita.

Muchidimbu, mainjiniya eCAM anoita basa rakakosha mukudzora kusagadzikana mumagadzirirwo ePCB kuburikidza nekunyatsoongorora, optimization yedhizaini dhizaini, kugadziridzwa kweiyo trace geometries, inodzorwa yekugadzira maitiro, yemhando yekudzora bvunzo, uye zvinyorwa. Unyanzvi hwavo uye kutarisisa kune zvakadzama kwakakosha pakuona kuita kwakavimbika kweakakwira-kumhanya emagetsi masisitimu.

Verification yeImpedance Control muPCB Manufacturing

Mushure meiyo yakadhindwa yedunhu bhodhi (PCB) yagadzirwa, zvakakosha kuti utarise impedance control kuti uve nechokwadi chechiratidzo chekuvimbika uye kuvimbika. Iyi yekusimbisa maitiro inogona kuitwa uchishandisa bvunzo makuponi, ayo anoshanda seyakajairwa bvunzo zvimiro zvakabatanidzwa muPCB yekugadzira maitiro. Heano maitiro ekuti impedance control verification process inowanzoitika:

Kugadzira uye Kuisa Makuponi Ekuyedza : Makuponi ekuyedza akagadzirirwa kumiririra zvivakwa zvakasiyana-siyana zvinodzorwa ne impedance zviripo paPCB, zvakaita semitsetse yekutumira kana kuti matrace e impedance. Makuponi aya akagadzirwa pane imwe panel sePCB, anowanzoiswa munzvimbo dzakasiyana panel yese kuti ape sampuro inomiririra hunhu hwe impedance yePCB.

Kushandiswa kweMakuponi eKuedza : Kana maPCB agadzirwa, makuponi ekuyedza anoshandiswa kuongorora mhando yemaitiro ekugadzira. Makuponi aya anoongororwa kuti ave nechokwadi chekuti akarongeka zvakanaka, kubatana kwemagetsi, uye kuvimbika kwechimiro. Pamusoro pezvo, ongororo yezvikamu zvinogona kuitwa kuti iongorore maficha emukati uye kuona kuti zvinoenderana nezvinodiwa pakugadzira.

Kuyedzwa kweTime-Domain Reflectometer (TDR) : Nzira huru yekusimbisa kudzora impedance inosanganisira kushandisa Time-Domain Reflectometer (TDR). TDR inogadzira mapulse emagetsi ane frequency yepamusoro anotumirwa pamwe chete nemitsetse yekutumira ye test coupon. Nekuongorora ma reflections emapulse aya, hunhu hwe impedance yemitsetse yekutumira inogona kutsanangurwa nemazvo.

Mushumo weKuedza Kudzivirira : Mushure mekuyedzwa kweTDR, mushumo wakazara unogadzirwa kuti upfupise hunhu hwekudzivirira kwePCB. Mushumo uyu unoratidza kana zvinangwa zvekudzivirira zvakatsanangurwa mudhizaini zvakabudirira panguva yekugadzira. Chero kutsauka kana kusawirirana kunyorwa kuti kuongororwe zvakanyanya uye kugadziriswe kana zvichidikanwa.

Pamusoro peiyo impedance control verification, zvakakosha kuti utarise zvimwe zvinhu zvinopesvedzera kuita kwese uye electromagnetic kuenderana (EMC) maitiro emidziyo yemagetsi. Mafungiro akakosha anosanganisira:

• Decoupling Capacitors: Kusarudzwa kwakakodzera uye kuiswa kwe decoupling capacitors kwakakosha pakugadzirisa kushanduka kwemagetsi uye kuderedza ruzha mumagetsi ekugovera network. Huwandu uye nzira ye decoupling capacitors inofanirwa kunyatso kwenenzverwa kudzikisa loop inductance uye kuve nechokwadi chekudzvinyirira ruzha.
• Plane Capacitance: Iyo magetsi ekugovera network inofanirwa kupa yakakwana ndege capacitance kuti igadzirise miganhu yeruzha uye kuchengetedza yakagadzikana mazinga emagetsi pamagetsi akasiyana ekupa. Dhizaini chaiyo yemagetsi nendege dzepasi kwakakosha mukuderedza impedance uye kuve nechokwadi chekupa simba kwemagetsi.
• Reference Plane Continuity: Kuchengetedza kuenderera mberi pakati pezvirongwa zvendege zvakakosha pakugadzirisa nzira dzazvino dzekudzoka uye kuderedza kukanganiswa kwechiratidzo. Discontinuities mukuenderera mberi kwendege kunogona kukonzera kuwedzera inductance uye kuderedza kutendeseka kwechiratidzo.
• Component Packaging: Kutarisisa kunofanirwa kubhadharwa kune kurongedza kwezvikamu kuti uderedze inductance uye kuve nechokwadi chekuita kwechiratidzo. Zvisizvo zvakagadzirirwa zvikamu mapakeji zvinogona kuunza zvisingadiwe inductances uye impedance mutsauko, zvichikanganisa kuita kwedunhu uye EMC maitiro.

Nekugadzirisa izvi zvinotariswa padivi peiyo impedance control verification, mainjiniya anogona kukwidziridza mashandiro uye kuvimbika kwePCB magadzirirwo, kuve nechokwadi chekutevedzera dhizaini uye indasitiri zviyero.

mhedziso

Sezvo mashandisirwo ezvishandiso zvekumhanya zvakanyanya kunowedzera, PCB vagadziri vanofanirwa kuzvidavirira kune zvakasiyana siyana zvinogona kukanganisa PCB kuita. Pakati pezvinhu izvi, impedance control inobata zvakakosha nekuda kwekuita kwayo pakutendeseka kwechiratidzo uye kushanda kwebhodhi rose. Nekunzwisisa zvikonzero zvekusapindirana kwe impedance uye kuwana hunyanzvi hunodiwa mukugadzira maitiro akanangana nekudzikisa kana kubvisa nyaya dzeimpedance, PCB vagadziri vanogona kugadzira mhinduro dzakanyatsogadzirwa.

Iyo yakasimba dhizaini, inobatanidza inobudirira impedance control matanho, inogona kushandurwa kuita yakavimbika uye yepamusoro-inoita yakadhindwa redunhu bhodhi. Izvi zvinosanganisira kunyatsotarisisa kune zvakadzama mukugadzira dhizaini, kusarudzwa kwezvinhu, uye maitiro ekuona. Nekuomerera kune akanakisa maitiro uye kusimudzira maturusi epamberi uye matekiniki, vagadziri vanogona kukwidziridza impedance hunhu uye kuve nechokwadi chekufambisa kwemasaini kutapurirana muPCB yese.

Muchidimbu, impedance control haingori chinodikanwa chehunyanzvi asi ibwe repakona rekubudirira kwePCB dhizaini muindasitiri yemazuva ano inomhanya-mhanya yemagetsi. Nekuisa pamberi pekufunga nezve impedance uye nekuibatanidza zvisina musono mudhizaini yekufambisa, vagadziri vanogona kusimudzira zviyero zvepamusoro zvekuita, kuvimbika, uye kushanda mumaPCB avo.