Ho utloisisa Phetiso ea Letšoao ho Li-PCB tsa Maqhubu a Phahameng

Selelekela

Lipotolohong tse tloaelehileng tsa maqhubu a tlase, mats'oao a ts'oaroa e le mefuta e bonolo ea motlakase e tsamaeang ho li-conductors. Leha ho le joalo, ha maqhubu a ts'ebetso a ntse a eketseha sebakeng sa gigahertz, boitšoaro ba matšoao bo fetoha haholo. Phetisetso ea leqhubu la maqhubu a phahameng e bonts'a litšobotsi tsa maqhubu a motlakase ho fapana le ho phatlalatsoa habonolo ha motlakase, ho hlahisa mathata a joalo ka lipontšo, crosstalk, le tahlehelo e itšetlehileng ka frequency. Lisebelisoa tsa sejoale-joale likhokahanong tsa mehala, lits'ebetso tsa radar, le komporo ea lebelo le holimo li hloka taolo e nepahetseng ea hore na matšoao a ata joang ka liboto tsa potoloho tse hatisitsoeng ho boloka ts'ebetso ea sistimi.

Kamoo Phetiso ea Letšoao la Maqhubu a Phahameng e Sebetsang ho PCBs

1. Ho Tloha ho Maqhubu a Tlase ho ea ho Boitšoaro ba Maqhubu a Phahameng

Libakeng tse tlase moo litekanyo tsa potoloho li lulang li le nyane haholo ho feta leqhubu la maqhubu, baqapi ba ka iphapanyetsa litlamorao tsa mohala oa phetisetso mme ba sebelisa melao e bonolo ea potoloho. Ha maqhubu a ntse a eketseha, maqhubu a maqhubu a bapisoa le bolelele ba mohlala oa PCB, ho qobella ho nahanoa ka litšobotsi tsa phatlalatso ea maqhubu. Phetiso ea matshwao a maqhubu a phahameng a tlameha ho ikarabella bakeng sa tieho ea nako ha matla a motlakase a ntse a tsamaea hammoho le li-conductors, e leng se etsang hore mohopolo oa phetiso e be oa bohlokoa. Phetoho ena hangata e ba ea bohlokoa ha linako tsa ho phahama ha lets'oao li theoha ka tlase ho nanosecond e le 'ngoe kapa maqhubu a feta 1 GHz.

2. Karolo ea Lithapo Tsa Phetiso

Mehala ea phetisetso moralong oa PCB e sebetsa e le litsela tse laoloang bakeng sa phatlalatso ea maqhubu a motlakase. The impedance character (Z₀) e emela karo-karolelano ea motlakase ho ea hona joale bakeng sa leqhubu le tsamaeang 'me e itšetlehile ka trace geometry le thepa ea dielectric. Litlhophiso tsa Microstrip li beha mesaletsa ea matšoao holim'a likarolo tse ka ntle tse nang le lifofane tse ka tlase, ha stripline e etsa matšoao a sandwich lipakeng tsa lifofane tse peli tsa litšupiso. Kamano e teng lipakeng tsa trace ea lets'oao le sefofane sa eona sa litšupiso e etsa qeto ea kabo ea tšimo ea motlakase, e amang ka kotloloho hore na phetisetso ea leqhubu la maqhubu a phahameng e boloka botšepehi ho pholletsa le boto.

Lintlha tsa Bohlokoa tse Amang Phetiso ea Letšoao la Maqhubu a Phahameng

1. PCB Material Properties

Sephetho sa dielectric (Dk) se lekanya lebelo la phatlalatso ea lets'oao, ha tangent ea tahlehelo (Df) e lekanya ho qhalana ha matla e le mocheso nakong ea phetiso. Lisebelisoa tse tloaelehileng tsa FR4 li sebetsa ka ho lekaneng ka tlase ho 5 GHz empa li bontša tahlehelo e kholo maqhubung a phahameng. Lisebelisoa tse tsoetseng pele joalo ka li-laminate tse ikhethileng tsa laminate tse nang le tahlehelo e tlase kapa li-substrate tse thehiloeng ho PTFE li fana ka thepa e tsitsitseng ea dielectric le lintlha tse fokolang tsa tahlehelo tse hlokahalang bakeng sa lits'ebetso tse hlokang. Khetho ea thepa e ama ka kotloloho bandwidth e ka finyelloang, ho fokotseha ha lets'oao, le meeli ea moralo.

2. Trace Geometry le Impedans Control

Ho latela bophara, botenya, le sebaka sa sebaka se ipapisitseng le lifofane tsa litšupiso li theha lets'oao la mehala ea phetisetso. Ho boloka geometry e ts'oana ho pholletsa le litselana tsa matšoao ho thibela ho khaotsa ho thibela ho hlahisa maikutlo le ho senya ts'ebetso ea phetisetso ea maqhubu a phahameng. Matla a ho kopanya lipakeng tsa mesaletsa ea matšoao le lifofane tsa litšupiso a etsa qeto ea ho boloka botšepehi ba waveform ho pholletsa le sebopeho sa PCB.

3. Tsela ea ho Khutlela le ho Theha

Letšoao le leng le le leng la hona joale le hloka tsela ea ho khutla e bonts'ang mohlala oa lets'oao ka tlase ho lona sefofaneng se haufi sa litšupiso. Ho robeha kapa litšitiso tseleng ea ho khutla li qobella ho kheloha hona joale, ho theha loop inductance e nyenyefatsang boleng ba matšoao le ho eketsa tlhahiso ea motlakase. Li-stackups tse nang le mekhahlelo e mengata tse nang le lifofane tsa fatše tse inehetseng li fana ka litsela tse fokolang tsa ho khutla, ha leano ka ho behoa haufi le phetoho ea lera le boloka mokhoa oa ho khutla bakeng sa phetisetso ea maqhubu a phahameng a phahameng.

4. Via le Discontinuity Effects

Vias e theha li-impedance discontinuities ka matla a bona a parasitic le inductance, e bakang lipontšo tse sa fellang. Ka li-stubs-likarolo tse sa sebelisoeng tsa masoba a phunyeletsoeng a fetelang ka nqane ho lera la lets'oao-e sebetsa joalo ka meaho e matla e nyenyefatsang ts'ebetso ka holimo ho 5 GHz. Ho cheka ka morao ho tlosa li-stubs, ho sebelisa li-vias tse foufetseng kapa tse patiloeng, le ho ntlafatsa li-geometri tsa pad ho fokotsa liphello tsena ho botšepehi ba phetisetso ea maqhubu a phahameng.

Mathata a Tloaelehileng ho Phetiso ea Letšoao la Maqhubu a Phahameng

Ponahatso ea lets'oao e etsahala ha ho na le ho se lumellane ho itseng tseleng ea phetisetso, ho etsa hore likarolo tse ling tsa matla a fetisoang li khutlele morao ho ea mohloling. Maikutlo ana a theha maqhubu a emeng, a thunya ho feta tekano, le ho lla ho ka tsosang maemo a fosahetseng a kelello. Maano a nepahetseng a ho felisa - letoto, parallel, kapa pheliso ea AC - a tsamaisana le litšitiso ho fokotsa maikutlo:

• Pheliso ea letoto - Sehanyetsi sa libaka mohloling ho tsamaisana le impedance ea mokhanni, e loketseng likhokahano tsa ntlha-to-point
• Pheliso e tšoanang - E hokela mohanyetsi ho fana ka thepa kapa fatše qetellong ea ho amohela, e sebetsang bakeng sa meroalo e mengata
• Ho felisoa ha AC - E sebelisa marang-rang a RC ho fokotsa likhakanyo ha e ntse e fokotsa tšebeliso ea matla a DC

Crosstalk e hola ha khokahano ea motlakase lipakeng tsa mesaletsa e haufi e lumella mats'oao ho kenya li-voltage tse sa batleheng ho li-conductors tse haufi. Ho eketsa karohano ea trace, ho sebelisa pontšo ea phapang, le ho beha mesaletsa ea fatše pakeng tsa matšoao a bohlokoa ka katleho ho laola crosstalk ka meralo ea phetisetso ea maqhubu a phahameng.

Tšitiso e sa lumellaneng lipakeng tsa likarolo tse fapaneng tsa mats'oao - li-trace, vias, lihokelo, kapa likaroloana - e bokellana ho pholletsa le liphetoho tse ngata mme e ama ts'ebetso haholo. Le liphapang tsa 5-10% tsa impedance li ka baka tšenyo e lekantsoeng ka holimo ho 10 GHz, e hlokang mamello e tiileng ea tlhahiso.

Mekhoa ea ho Rala ho Ntlafatsa Phetiso ea Letšoao la Maqhubu a Phahameng

Moralo o laoloang oa impedance o qala nakong ea moralo oa li-stackup mme o tsoela pele ka mokhoa oa ho latela. Lisebelisoa tsa ho rarolla masimong li bala litekanyo tse hlokoang bakeng sa li-impedances tse boletsoeng-hangata 50 ohms single-end kapa 100 ohms differential-accounting bakeng sa thepa ea dielectric, boima ba koporo le mamello ea ho etsoa. Mokhoa ona o hlophisitsoeng o tiisa hore phetisetso ea maqhubu a phahameng a maqhubu a kopana le lipehelo tsa ts'ebetso.

Lisebelisuoa tsa dielectric tsa tahlehelo e tlase tse loketseng lebelo la maqhubu a kopo li ntlafatsa ka kotloloho ho boloka mats'oao a amplitude. Le ha lisebelisoa tsa premium li eketsa litšenyehelo, lia hlokahala ha li sebetsa ka holimo ho 10 GHz kapa ha likhakanyo tsa tahlehelo ea ho kenya li thibetsoe:

• FR4 e tloaelehileng – E lekane bakeng sa maqhubu a ka tlase ho 5 GHz, Dk ~4.2-4.5, Df ~0.02
• Lisebelisoa tsa tahlehelo ea bohareng - laminate e khethehileng e nang le tahlehelo e tlase bakeng sa lits'ebetso tsa 5-20 GHz, Dk ~3.48, Df ~0.0037
• Lisebelisoa tsa tahlehelo e tlase - laminate e khethehileng e nang le tahlehelo e tlase kapa PTFE-based for above 20 GHz, Dk ~3.0, Df ~0.001

Ketsiso ea ponts'o ea ponts'o e sebelisang li-electromagnetic field solvers e netefatsa meralo pele e etsoa. Lisebelisoa tsena li bolela esale pele li-profiles tsa impedance, maemo a crosstalk, tahlehelo ea ho kenya, le li-waveform tsa nako-domain tlasa maemo a fapaneng a ts'ebetso. Ketsiso ea pejana e supa mathata ha litokiso li hloka feela liphetoho tsa moralo ho fapana le li-respins tsa boto tse turang, ho netefatsa hore ts'ebetso ea phetisetso ea maqhubu a phahameng e kopana le lipehelo.

Tsoelo-pele ea tsela ea ho khutla e hloka tlhokomelo nakong ea moralo oa stackup le ho beha likarolo. Likarolo tsa matšoao li lokela ho lula li bua ka lifofane tse haufi ntle le tšitiso:

• Lifofane tse tiileng tsa litšupiso - Qoba ho arohana ka tlas'a litsela tse lebelo le phahameng ho boloka litsela tsa morao-rao tse khutlang
• Liphetoho tsa lera - Beha fatše ka tsela e haufi le lets'oao ha u fetola likarolo
• Lifofane li fetoha - Sebelisa stitching vias ho hokahanya lifofane tsa litšupiso ha lipontšo li tšela mefuta ea lifofane

Ho netefatsa litsela tse tsoelang pele tsa ho khutla ho fokotsa tšitiso ea motlakase le ho boloka botšepehi ba matšoao ho pholletsa le meralo ea PCB e phahameng haholo.

fihlela qeto e

Phetisetso ea leqhubu la maqhubu a phahameng e emela phatlalatso ea maqhubu a motlakase e hlokang taolo e matla ea impedance, taolo e hlokolosi ea tsela ea ho khutla, le kutloisiso ea lintlha le lintlha tsa geometri tse amang botšepehi ba matšoao. Melao-motheo ena e theha motheo oa li-circuits tsa RF tse tšepahalang, li-interface tsa digital tsa lebelo le phahameng, le mekhoa e tsoetseng pele ea puisano e sebetsang ka maqhubu a mangata a gigahertz.

Ho Highleap Electronics, sehlopha sa rona sa boenjiniere se fana ka boiphihlelo moralong o laoloang oa impedance le tlhahiso ea PCB ea maqhubu a phahameng, ho thusa ho netefatsa botšepehi bo botle ba lets'oao bakeng sa litsamaiso tse rarahaneng tsa elektroniki. Ikopanye le rona ho buisana ka hore na bokhoni ba rona bo ka tšehetsa phephetso ea hau e latelang ea moralo oa maqhubu a phahameng joang.