Mitemo gumi yeLayer PCB Routing yeDDR5, PCIe neCrosstalk

Mitemo yekufambisa yePCB ine layer gumi inofanira kubva mu stackup, ma device design guides uye channel analysis. Haafanire kukopwa kubva patafura ye generic ye mil values. Kureba kwakaenzana hakurevi nguva dzose kunonoka kwakaenzana kwemagetsi, "mutemo we 5W" hausi vimbiso ye crosstalk, uye kugadzirwa kweprotocol hakungomiriri otomatiki laminate kana fixed residual kuburikidza ne stub.

Chinangwa chegwaro iri ndechekushandura zvinodiwa nemagetsi kuita zvirambidzo zvemarongerwo azvo zvinoramba zvichishanda kuburikidza nekugadzira. Rinotarisa panzira dzekudzoka, nzira dzakabatana, nguva yekurangarira, shanduko dzeserial-link, crosstalk uye kuendeswa kuDFM. Upamhi hwekupedzisira nemaburi zvinobva kumuenzaniso we impedance wakaburitswa.

Bvisa Mitemo yeMagetsi Usati Watanga Kufamba

Kuronga marongero hakufanirwe kutanga nekukora kwechinguvana kwe dielectric uye kupedzisa nekukumbira mugadziri "kugadzirisa stackup kuti ikwane." Kuchinja stackup kunochinja upamhi, nzvimbo yepakati pemaviri, kunonoka kwekupararira, kugoverwa kwereferensi uye dzimwe nguva kugona kwe layer. Package yekutanga inofanira kuratidza stackup revision, kuvaka kwezvinhu, mhangura, zvimiro zvinodzorwa, mitemo yenguva yakatarwa nemidziyo uye mamodheru emagetsi anoshandiswa kuma channel akakosha.

Shandisa urongwa hwemitemo. Zvinodiwa zvemudziyo kana chimiro-chazvo zvinodarika mutemo wekambani; musiyano wakaedzwa unofanirwa kunyorwa; uye huwandu hwezvinhu zvakagadzirwa imiganhu, kwete zviyero zvekufambisa zvinosarudzwa.

Basa reLayer uye Kuenderera Mberi kweNzira Yekudzoka

Nzira yega yega inomhanya zvakanyanya inoda mutungamiriri wekutarisa nguva dzose. Pachikamu chegumi chezviratidzo chakafanana, zviratidzo zvekunze zvinotarisa mapuraneti epasi ari pedyo uye zviratidzo zvemukati zvakasarudzwa zvinoiswa pakati pemapuraneti maviri epasi. Kurongeka ikoko kunobatsira nekuti magetsi ekudzoka anogona kuramba ari pedyo nechiratidzo. Mamwe mapuraneti anogona kushanda, asi mitemo yekuronga inofanira kuratidza mareferensi avo chaiwo.

Usapfuure nepakati penzvimbo yekupatsanurana

Kana trace ikayambuka nzvimbo isina chinhu kana yakakamurwa mu reference plane yayo, dzorera macurrent detours akatenderedza buri, uchiwedzera loop area uye ukabatana mune zvimwe zvivakwa. Kuendesa trace kune layer ine continuous reference kazhinji zviri nani pane kuwedzera capacitor mushure mekurongeka. Kana power plane ikashandiswa nemaune se high-frequency reference, kubatana kwayo neground domain yakakodzera kunofanira kunge kuri chikamu chedhizaini.

Kuchinja kwezvikamu kunoda shanduko yekudzoka

Chiratidzo kuburikidza nekufambisa magetsi epamberi pakati pezvikamu; magetsi ekudzoka anodawo nzira pakati pezvinyorwa zvekare nezvitsva. Kuchinja kubva pasi kuenda pasi kunowanzo shandisa ma-vis ekusona ari pedyo. Kuchinja kubva pasi kuenda pasi kungada chimiro chakagadziriswa kuitira kuti chiuno chekudzoka chive chidiki chinogamuchirika pamusoro pehuwandu hwakakodzera. "Chimwe chinhu chakavharwa mukati me50 mil" mutemo weheuristic, kwete mutemo wepasi rose.

Zviratidzo zviri pedyo

Kufamba kwetsoka netsoka kunogona kuderedza kubatana kwepakati pezvikamu zvezviratidzo zviri pedyo, asi hazviiti kuti kuungana kwakashata kuve kusina njodzi. Kana zvikamu zviviri zvezviratidzo zvakatarisana pasina kuenzana pakati pazvo, deredza kupindirana, wedzera kuparadzaniswa uye chengeta zviviri izvi kuti zvisanyanya kubatwa nemhepo. Kune zvikamu zvakakosha zvekubatanidza, kufamba kwakaparadzaniswa nendege ndiko kunosarudzwa.

Kusiyana kweMapairi: Geometry, Skew uye Transitions

Peya yakasiyana inofanira kuchengetedza nharaunda yemagetsi yakafanana. Upamhi, nzvimbo pakati pemaviri, daro rekutarisa uye mhangura iri pedyo zvinofanirwa kuramba zviri mukati mechimiro chinoshandiswa pakuverenga impedance. Kudzika kwemutsipa kupfupi pamapedhi kunogona kusadzivisika, asi kunofanirwa kuenzaniswa kana kuchengetwa mukati menzvimbo yakasimbiswa.

Kuskewa kwemukati mevaviri huwandu hwemagetsi

Chinja nguva yakabvumirwa kuita urefu uchishandisa kunonoka kwekupararira kwechinhu chiri padanho rakarongwa. Peya inochinja ma layer inogona kuva nehurefu hwakaenzana asi kunonoka kusina kuenzana kana ma traces maviri akaedza girazi rakasiyana, shandisa zvakasiyana kuburikidza ne geometry kana kusangana nekuchinja kwakasiyana kwe reference. Kune ma link anomhanyisa zvakanyanya, bvisa kunonoka uye kushandura mode pane kungovimba chete nehurefu hwepakati pePCB tool.

Chengeta shanduko mbiri dzakaenzana

Chiratidzo kuburikidza nemapadhi, maantipadhi, mareferensi uye kubuda kwechiratidzo kunofanirwa kunge kwakaenzana negirazi kana zvichibvira. Dzivisa kuisa chiratidzo chimwe chete pedyo nepasina chinhu, gomba rekukwidza kana chishongo chekubatanidza. Kana polarity inversion ichibvumidzwa neinterface, ishandise nemaune pane kuwedzera crossover refu kuchengetedza maonero.

Kufananidzana kwevaviri vaviri hakudiwi otomatiki

Mazhinji ma serial receivers anoshandisa nzira dzekubvisa ma serial, saka kumanikidza ma PCIe ese kana ma SerDes kuti aenderane nehurefu hwemuviri kunogona kuwedzera kurasikirwa kusingakoshi uye kutenderera. Tevedzera zvinodiwa ne governmental lane-to-lane skew, asi tanga ne low loss, clean return paths uye ma transitions mashoma. Intra-pair skew inowanzo kuve yakakosha pane kuenzanisa nzira dzisina hukama.

DDR5 nedzimwe Parallel Memory Interfaces

Zvirambidzo zveDDR5 zvinoenderana nepakeji yemutongi, kurongeka kweDRAM, module kana down topology, speed bin, loading uye termination. Chitubu chakakodzera igwara rekugadzira remutongi nememory vendor, rinotsigirwa nemamodeli ekufananidzira. Chirevo chakajairika chakadai sekuti "DQ inofanira kuenderana mukati me +/-5 mil" chinogona kunge chakamanikana zvisina kufanira kana kuti chisina kuchengetedzeka kune imwe puratifomu.

Mitemo yeboka nemabasa

Tsanangura mapoka akasiyana eDQ/DMI zvichienzaniswa neDQS, wachi yedhizaini, command/address/control uye chero zviratidzo zvemodule-specific. Shandisa zvirambidzo zvekunonoka mupicoseconds pazvinogoneka, nekuti urefu hwemuviri hunoshanduka zvakasiyana pazvikamu zvakasiyana. Chishandiso chekuronga chinogona kushandisa kunonoka kwezvikamu pane kufunga kuti chimwe chinhu chinoramba chichipararira.

Nyaya dzeTopology

Mirairo/kero newachi zvinogona kushandisa topology inobhururuka-ne-nzira mumagadzirirwo akavakirwa pamodule, nepo masaini edata ari source-synchronous point-to-point connections mukati me byte lane. Magadzirirwo edown, mamodule akanyoreswa uye ma buffered modules anounza kurodha kwakasiyana uye nzira. Usakope topology yeDIMM pane dhizaini yakasungirirwa-nenzira isina gwaro repuratifomu.

Kutendeseka kwesimba uye hunhu hwekutaura

Nguva yekurangarira inokanganiswa neruzha rwereferensi-ndege uye kugoverwa kwesimba pamwe nehurefu hwetrace. Chengetedza nzira dzebyte munzvimbo yakagadzikana yereferensi, ipa kurapwa kwakakodzera kweVREF neVDDQ, uye dzivisa kuisa zvivakwa zvekugadzirisa pamusoro pemaburi endege. Tevedzera maitiro ekuchinja panguva imwe chete uye ekupedzisira kana puratifomu iri shoma.

PCIe uye High-Speed ​​​​Serial Links

Kune PCIe Gen5 uye gare gare, mhando yenzira inodzorwa nekurasikirwa kunoenderana nefrequency, connector uye kuburikidza ne discontinuities, crosstalk uye mode conversion. Saka, seti yemitemo yekurongeka inofanira kusanganisira zvinopfuura target impedance.

PCIe 6.0 inoshandisa PAM4 pa64 GT/s ine frequency yakafanana ye16 GHz Nyquist sePCIe 5.0 NRZ, asi haisi "chiteshi chimwe chete chine mabhiti maviri." Kutevedzera mitemo, ruzha uye mamiriro eFEC zvakasiyana. PCIe 7.0 pa128 GT/s inofambisa frequency yeNyquist kuenda ku32 GHz uye inoita kuti kuburitsa shanduko uye kubatana kwekugadzira kuve kwakaoma.

Ruzha rweCrosstalk, Spaceing uye Reference-Plane

Mutemo we3W kana 5W unowanzo taurwa unoenderana ne geometric heuristic. Crosstalk inoenderanawo nekukwirira kwe dielectric, kureba kwakafanana, nguva yekukwira kwe aggressor, chimiro che reference uye kana mitsetse yacho yakabatana nechekumucheto kana kuti broadside. Pa dielectric yakatetepa, space diki inogona kutosvika pachinangwa; pa masignal layers ari pedyo asina reference, space yakakura inogona kunge ichiri isina kukwana.

Isa chinangwa chekutaurirana chakakodzera interface uye shandisa tafura yekubvisa kana yejometri yakagadziriswa kuti ushandure chinangwa ichocho kuita nzvimbo. Funga nezvehurefu hwemunhu anenge abatwa uye vanhu vanorwisa panguva imwe chete. Clock, strobe uye high-swing single-end nets zvinogona kukodzera kuparadzaniswa kupfuura kudzora kunonoka kusina hukama.

Ruzha rweplane runogona kuenderana nechimiro chereferensi kunyangwe kana nzvimbo yekutevedzana kwetrace-to-trace yakakura. Chengetedza switching loops dzakasimba, shandisa ma plane pairs akakodzera uye bvisa coupling, uye dzivisa kumanikidza ma sensitive traces kune reference fragmented power islands. Crosstalk ne power integrity zvinofanirwa kuongororwa pamwe chete pama dense processors nema accelerator boards.

Kugadzirisa Urefu Pasina Kugadzira Kusawirirana Kutsva

Ma "meanders" anowedzera kunonoka, asi zvikamu zvakataramukana zvinobatana uye zvinopa kunonoka kushoma pane hurefu hwepakati pazvo. Zvinowedzerawo kurasikirwa uye zvinogadzira musiyano we "local impedance". Shandisa nzvimbo yakakura pakati pezvikamu zve "tuning" zviri pedyo, deredza huwandu hwe "turns" uye govera "tuning" paisingakanganisi "breakouts" kana "reference continuity".

Hapana mutemo wepasi rose wekuti kugadzirisa kunofanira kunge kuri pedyo nekwakabva kana pedyo nekwakagamuchira. Kuiswa kwacho kunoenderana ne topology uye chinangwa chekubatana. Kune bhasi rinoenderana ne source, gadzirisa mukati meboka rakatsanangurwa uye chengetedza topology. Kune differential pair, gadzirisa skew ine chimiro chakamanikana, chakaenzana chisingagadzire chikamu chirefu chisina kubatana.

Makona akatenderera haadiwi otomatiki, uye kukotama kamwe chete kwemadhigirii makumi mapfumbamwe hakusi kuratidzwa kwe15% mune yega yega geometry. Shandisa nzira yekutenderera yemadhigirii makumi mana nemashanu kana yakakombama kuti ugone kugadzira, kuenzana kwemaviri uye nzvimbo dzakafanana, asi tarisa simba reinjiniya pane kusagadzikana kukuru senge mapedhi, mavhia, maconnector uye mareferensi-plane breaks.

Kubuda muBGA, Mavhiza uye Kugona Kugadzirwa

BGA pitch yega haisarudze kana HDI ichidiwa. Dhayamita yepad, solder-mask strategy, huwandu hwemitsara, pin map, routing layers dziripo uye escape direction zvese zvine basa. Mimwe michina ye 0.5 mm-pitch inogona kushandisa nzira yakagadzirwa zvakanaka ye through-via kana limited blind-via; mimwe inoda via-in-pad uye akawanda buildup layers. Ongorora package fanout chaiyo pane kushandisa pitch-only table.

Via-in-pad inofanira kutaura kana via yakazadzwa nemhangura, yakazadzwa neresin uye yakavharirwa, kana kuti inobatwa neimwe nzira yakakodzera. Kune ma microvia akaunganidzwa, kurongeka kwekuvaka uye hurongwa hwekuvimbika kunofanirwa kubvumirana. Gwaro reHDI rinofukidza kusarudzwa kwechivako; marongerwo anofanira kuramba achipa nzvimbo dzekutora, antipads uye kuchengetedza zvinoenderana nekugona kwemutengesi kunyoresa.

Nzira yekubuda nayo inofanirawo kuchengetedza kuenderera mberi kwereferensi. Nzvimbo dzakasimba dzekudzivirira madhiraivha dzinogona kubvisa mhangura yakawanda pasi pepakeji, saka simba nekubuda kwepasi zvinofanirwa kuongororwa sechimiro chemagetsi. Kuwedzera mamwe madhiraivha epasi hakubatsiri nguva dzose kana kuchimanikidza madhiraivha akakura kana kudzivirira nzira yekubuda.

Ongororo yeMarongero Ekugadzira Zvinhu Pamberi Pekugadzira

Ongororo yeDFM haifanirwe kunyora zvirambidzo zvemagetsi chinyararire. Kana CAM ikakurudzira shanduko yehupamhi, padhi, antipad kana stackup, shanduko yacho inofanira kuongororwa zvichienderana ne impedance kana chiteshi modhi uye yakanyorwa. Tumira dhizaini yekupedzisira pamwe nedhirowa yekugadzira uye netlist kuburikidza nemaitiro ekuongorora eDFM.

Kutangwa kweConnector, Miganhu yeBhodhi uye Maumbirwo eMiedzo

Kuburitswa kweconnector kunowanzova kusaenderera mberi kukuru kupfuura kukotama kwakajairika. Ongorora signal pad, antipad, ground pin pattern, plane cutouts uye shanduko mu routed pair sechimiro chimwe chete. Ma footprints evatengesi ndiwo ekutanga, kwete vimbiso, nekuti ukobvu hwebhodhi, kugoverwa kwe layer uye saizi yekugadzira zvinogona kusiyana. Kune connectors dzinomhanya zvakanyanya, shandisa modhi yemutengesi uye bvisa PCB launch yemuno.

Pamipendero yebhodhi, dzivisai kudzima kamwe kamwe kwereferensi-plane pasi penzira inonzwisisika. Kubatana kwemakadhi, coax launches uye mezzanine connectors zvinogona kuda kuumbwa kwevhu, kuburikidza nefenzi kana shanduko dzemunzvimbo dzakatarwa dzine chekuita neinterface. Chengetedza kuchengetedza kwemechanical, plating bars uye breakaway tabs kure nenzvimbo yereferensi yemagetsi kunze kwekunge zvabatanidzwa mumodhi.

Gadzira mukana wekuyedza pasina kugadzira zvidimbu zvemapepa

Mapedhi eprobe akajairwa uye nzvimbo dzekuyedza dzakagadzirwa nemashizha zvinogona kuwedzera capacitance kana stub isina kugadzikiswa. Shandisa coupon yekuyedza yakasimbiswa, mukana wekubatanidza, sarudzo yechikamu chinobviswa kana pad yakabatanidzwa munzira huru yekutumira. Gadzirisa zvinodiwa zvekuyedza mukati medunhu nekuvimbika kwechiratidzo usati wapedza kuronga; kubvisa bazi rekuyedza mushure mekuongororwa kunogona zvakare kuchinja chiteshi.

Nyora zvisiri izvo nemaune

Marongerwo enzvimbo dzakakora dzimwe nguva anoda shanduko yehupamhi hwenzvimbo, shanduko yereferensi kana kutyorwa kwenzvimbo. Nyora nzvimbo, chikonzero uye simulation kana mvumo yemutengesi. Kusabvumidzwa kwakanyorwa kwakachengeteka pane kuregeredza mutemo wepasi rose kana kuvimba neinjiniya weDFM wemangwana kuti afungidzire chinangwa chekugadzira.

Miganhu yeWachi, Analog uye Power Routing

Haasi ese ma network akakosha ari differential serial link. Mawachi ereference, ma reset signals, analog sensor paths uye switching-power nodes zvinogona kugadzira kana kugamuchira kukanganiswa. Ronga ma network ne edge rate, noise sensitivity uye current loop pane kushandisa nominal frequency chete. Wachi ine low-frequency ine fast edge inogona kuda kutarisirwa kupfuura higher-frequency sine wave.

Maawa ekutaridza

Dzorera wachi dzekutarisa pamusoro penzvimbo inoenderera mberi, dzivisa ma stubs ekuyedza asina kufanira uye dziparadzanise kubva pakuchinja ma nodes. Topology inodiwa - point-to-point, fanout buffer kana imwe nzira yekugovera - inobva kunobva wachi uye ma receiver specifications. Nyeredzi kana daisy chain haisi yakarurama zvachose. Kana ma receiver akawanda achifambiswa, tevedzera kurodha nekugumisa.

Ma interfaces eAnalog neConverter

Chengeta madiki madiki eanalog akabatana uye uaparadzanise kubva kuma "aggressive digital return currents". Kuparadzanisa "ground plane" hakubatsiri otomatiki; "continuous plane" ine nzvimbo yakanyatsofungwa inowanzopa "low-impedance return". Kana ma "analog" nema "digital domains" achifanira kubatana panzvimbo yakadzorwa, iva nechokwadi chekuti masaini haapfuure mukaha unobuda uye kuti nzira yekubatanidza inoenderana nenhungamiro yemutengesi we converter.

Nzvimbo dzesimba dzinochinja

Nzira dzemagetsi dzinoshandiswa pakuchinja magetsi, gate-drive loop, uye high-di/dt current paths dzinofanirwa kutorwa munzvimbo dzakasiyana. Usashandise high-speed pairs pasi pe inductors, transformers kana switch-node copper. Plane voids uye keep-outs zvinofanirwa kuratidzwa mu return-path review. Current-carrier width uye thermal performance zvinofanirwa kuongororwa nenzira dzeIPC-2152 kana kuti sumo yakasimbiswa pane nhamba yemagetsi inosanganiswa nemagetsi.

Nyora matunhu aya mumiganhu yekurongeka kuitira kuti kuwedzerwa kwemhangura yeDFM, kuba kana maficha epaneru asapinde munzvimbo inonetsa nemaune.

Kusaina Mutemo weRouting Rule

Ongororo yekupedzisira yekufambisa inofanira kuenzanisa marongerwo ne stackup yakaburitswa uye zvirambidzo zvemudziyo pane kutarisa generic ye mil values. Mapoka akakosha anofanira kuongororwa achishandisa ma extracted delay, loss and transition models apo mhedzisiro iyoyo inokosha.

• Iva nechokwadi chekuti nzira yega yega yakakosha inoramba iri pamusoro pechirevo chinoenderera mberi uye kuti shanduko dzezvikamu dzinopa nzira yekudzoka-yazvino.
• Tarisa magadzirirwo akasiyana-siyana kuburikidza nemutsipa, mapedhi, mavhiya, zvinobatanidza uye maumbirwo ebvunzo - kwete chete pamatanho akatwasuka.
• Shandisa nguva yekurangarira ne byte lane, command/address group uye topology uchishandisa controller ne memory documentation.
• Deredza kutenderera uye kufanana kwakavakirwa pakunonoka uye ongororo yekutaurirana pane kushandisa nzvimbo dzakasiyana-siyana.
• Simbisa BGA fanaut, annular rings, antipads uye via spans zvichienzaniswa nekugona kwemutengesi.
• Ipai mifananidzo yekupedzisira, netlist, data rekudhirowa/route, stackup revision, impedance table uye controlled-depth drawing seimwe package inodzorwa ne revision.

Mitemo yekurongeka kwemagetsi inofanira kuratidza chinangwa chemagetsi uye kwaanobva. Izvi zvinoita kuti zvisaririra zviongororwe uye zvinodzivirira shanduko yekugadzira kuti isaite kuti zvirambidzo zvekufambisa zvinhu zvisashande chinyararire.

Kugadzirisa Zvisizvo Zvekushandisa Pakufambisa Nzira

Marongerwo enzvimbo dzakamanikana anoda kusashandiswa pamitemo inofarirwa. Chinangwa hachisi chekurambidza kuderedzwa kwenzvimbo dzese dzinoshandiswa pamutsipa, kuchinja kwenzvimbo kana kuderedza nzvimbo dziri pedyo; ndechekuona kuti ndedzipi nzvimbo dzine kukosha pamagetsi uye kudziongorora nemuenzaniso wakakodzera.

Zvisizvo zvinofanirwa kubatanidzwa kumambure, matunhu kana makirasi uye kuchengetwa nerekodhi yekuongorora dhizaini. Mvumo yakapararira yakaita sekuti "nzvimbo inogamuchirwa" haigone kudzokororwa panguva yeECO kana kutamiswa kwemutengesi. Nheyo imwecheteyo inoshanda kumarongero ereferensi yemuchina nemutengesi: kuchengetedza chinangwa chemagetsi, asi kusimbisazve zviyero zvichienzaniswa nebhodhi rakaburitswa.

Rekodhi yekuongorora inofanirawo kuratidza shanduro yekuburitsa kana yekufananidzira inoshandiswa kune zvakakosha. Kana ECO ikafambisa chikamu, ikachinja layer kana kuchinja connector footprint, izvo zvakakanganiswa zvinogona kuongororwazve pachinzvimbo chekugara nhaka mvumo isingachaenderane ne geometry.