Don tabbatar da ingancin watsa sigina, rage tsangwama na EMI, da wuce takaddun gwajin da ya dace, PCB Ana buƙatar ƙira madaidaicin sigina impedance. Wannan jagorar ƙira ya dogara ne akan sigogin lissafin gama gari, halayen siginar samfurin TV, buƙatun shimfidar PCB, lissafin software na SI9000, bayanan mai ba da kayayyaki na PCB da sauransu, kuma a ƙarshe ya zo ga ƙirar da aka ba da shawarar. Ya dace da yawancin matakan tsari na masu samar da PCB da ƙirar hukumar PCB tare da buƙatun sarrafa impedance.

Daya. Ƙirar fuska biyu

① Ground zane: layin nisa, tazara 7/5/7mil ƙasa waya nisa ≥20mil sigina da ƙasa waya nisa 6mil, kowane 400mil rami rami; (2) Tsarin da ba a rufe ba: nisa layin, nisa 10/5 / 10mil bambancin nau’i biyu da nisa tsakanin nau’in biyu ≥20mil (yanayi na musamman ba zai iya zama ƙasa da 10mil ba) ana ba da shawarar cewa duka rukunin layin siginar daban ta amfani da enveloping. garkuwa, sigina daban-daban da nisan garkuwar ƙasa ≥35mil (al’amura na musamman ba za su iya zama ƙasa da 20mil ba). 90 ohm bambanci impedance shawarar ƙira

Faɗin layi, tazara 10/5/10mil Nisa na ƙasa ≥20mil Sigina da nisan waya na ƙasa na 6mil ko 5mil, rami mai ƙasa kowane 400mil; ②Kada a haɗa da zane:

Faɗin layi da tazara 16/5/16mil nisa tsakanin nau’in siginar banbanta ≥20mil ana ba da shawarar cewa a yi amfani da lullubi na ƙasa don duka rukunin kebul na siginar daban. Nisa tsakanin siginar banbanta da kebul na ƙasa mai kariya dole ne ya zama ≥35mil (ko ≥20mil a lokuta na musamman). Babban mahimman bayanai: ba da fifiko ga yin amfani da ƙirar ƙasa da aka rufe, gajeriyar layi da cikakken jirgin sama za a iya amfani da su ba tare da ƙirar ƙasa da aka rufe ba; Lissafi sigogi: farantin karfe FR-4, farantin kauri 1.6mm +/- 10%, farantin dielectric akai 4.4+/-0.2, jan karfe kauri 1.0 oz (1.4mil) solder man kauri 0.6 ± 0.2mil, dielectric akai 3.5 +/-0.3.

Impedance zane na biyu da hudu yadudduka

100 ohm bambanci impedance shawarar zane nisa da kuma tazara 5/7/5mil nisa tsakanin nau’i-nau’i ≥14mil (3W ma’auni) bayanin kula: ana ba da shawarar cewa a yi amfani da lullubi na ƙasa don duka rukunin kebul na siginar daban. Nisa tsakanin siginar banbanta da kebul na ƙasa mai kariya ya kamata ya zama aƙalla mil 35 (ba ƙasa da 20mil a lokuta na musamman ba). 90ohm bambanci impedance Ya ba da shawarar faɗin layin ƙira da tazara 6/6/6mil Bambancin nisa biyu ≥12mil(ma’auni 3W) Babban maki: Dangane da doguwar kebul na bambancin kebul, ana ba da shawarar cewa nisa tsakanin bangarorin biyu na layin bambancin kebul kunsa ƙasa da 6mil don rage haɗarin EMI (nannade ƙasa kuma kada ku nannade ƙasa, faɗin layi da daidaitattun nisa na layi daidai). Sigar lissafi: Fr-4, farantin kauri 1.6mm +/- 10%, farantin dielectric akai-akai 4.4+/-0.2, Copper kauri 1.0oz (1.4mil) Semi-warke takardar (PP) 2116 (4.0-5.0mil), dielectric akai 4.3+/ -0.2 solder man kauri 0.6 ± 0.2mil, Dielectric akai 3.5+/- 0.3 laminated tsarin: allo bugu Layer solder Layer jan karfe Layer Semi-warke film mai rufi jan karfe substrate Semi-warke film jan karfe Layer solder Layer allo bugu Layer

Uku. Six Layer Board impedance zane

Tsarin lamination na Layer shida ya bambanta don lokuta daban-daban. Wannan jagorar kawai yana ba da shawarar ƙirar lamination na gama gari (duba FIG. 2), kuma samfuran shawarwari masu zuwa sun dogara ne akan bayanan da aka samu a ƙarƙashin lamination a cikin FIG. 2. Tsarin impedance na waje na waje yana daidai da na allon Layer hudu. Saboda Layer na ciki gabaɗaya yana da ƙarin yadudduka na jirgin sama fiye da saman saman, yanayin lantarki ya bambanta da saman saman. Masu zuwa sune shawarwari don sarrafa impedance na layi na uku na wayoyi (laminated reference Figure 4). 90 ohm bambanci impedance Ya ba da shawarar faɗin layin ƙira, nisan layin 8/10 / 8mil Bambancin nisa biyu ≥20mil (ma’aunin 3W); Sigar lissafi: Fr-4, farantin kauri 1.6mm +/- 10%, farantin dielectric akai-akai 4.4+/-0.2, Copper kauri 1.0oz (1.4mil) Semi-warke takardar (PP) 2116 (4.0-5.0mil), dielectric akai 4.3+/ -0.2 solder man kauri 0.6 ± 0.2mil, Dielectric akai-akai 3.5+/- 0.3 laminated tsarin: saman allo tarewa Layer jan karfe Layer Semi-warke jan karfe-mai rufi substrate Semi-warke jan karfe-rufi substrate Semi-warke jan karfe-rufi Layer kasa allo tarewa Layer

Don fiye da yadudduka huɗu ko shida, da fatan za a tsara da kanku bisa ga ƙa’idodi masu dacewa ko tuntuɓi ma’aikatan da suka dace don tantance tsarin lamination da tsarin wayoyi.

5. Idan akwai wasu buƙatun kulawa da impedance saboda yanayi na musamman, da fatan za a lissafta da kanku ko tuntuɓi ma’aikatan da suka dace don sanin tsarin ƙira.

Lura: ① Akwai lokuta da yawa da suka shafi impedance. Idan PCB yana buƙatar sarrafa shi ta hanyar impedance, buƙatun sarrafa impedance yakamata a yi alama a sarari a cikin bayanan ƙirar PCB ko takaddar samfur; (2) 100 ohm bambanci impedance ne yafi amfani ga HDMI da LVDS sigina, a cikin abin da HDMI bukatar wuce da dacewa takardar shaida wajibi ne; ③ 90 ohm bambancin impedance ana amfani dashi don siginar USB; (4) Single-terminal 50 ohm impedance ana amfani dashi galibi don ɓangaren siginar DDR. Tunda yawancin ɓangarorin DDR suna ɗaukar ƙirar ciki daidai da ƙirar impedance, ƙirar ta dogara ne akan allon Demo wanda kamfanin mafita ya bayar azaman tunani, kuma wannan jagorar ƙira ba a ba da shawarar ba. ⑤, impedance 75-ohm-ƙarshen-ƙarshen ana amfani dashi galibi don shigarwar bidiyo na analog da fitarwa. Akwai juriya na 75-ohm wanda ya dace da juriya na ƙasa akan ƙirar kewayawa, don haka ba lallai ba ne don aiwatar da ƙirar matching a cikin PCB Layout, amma ya kamata a lura cewa juriya na ƙasa na 75-ohm a cikin layin yakamata a sanya shi kusa. zuwa fil fil. Yawan amfani da PP.