Ibhodi PCB I-impedance ibhekisela kwiiparameters zokuchasana kunye nokusabela, ezithintela ukutshintshwa kwangoku. Kwimveliso yeebhodi zeesekethe ze-PCB, ukulungiswa kwe-impedance kubalulekile. Kutheni iibhodi zesekethe zePCB zifuna i-impedance?

1. Isekethe ye-PCB (esezantsi kwebhodi) kufuneka ithathele ingqalelo ukuplaga kunye nokufakela izinto ze-elektroniki, kwaye i-conductivity kunye nokusebenza kokuhanjiswa komqondiso kufuneka kwakhona kuthathelwe ingqalelo emva kokuba i-patch ye-SMT yamva iplagwe. Ngoko ke, i-impedance ephantsi, ingcono, ngakumbi isignali ye-microwave. Kwisixhobo, imfuno yokumelana yile: ngaphantsi kwe-1&TImes;10-6 kwisikwere sesentimitha.

2. Kwinkqubo yokuvelisa iibhodi zeesekethe ze-pcb, kufuneka bahambe ngeenkqubo ezifana nokuntywiliselwa kobhedu, i-tin plating (okanye i-chemical plating, okanye i-thermal spray tin), i-soldering ye-connector, njl., kunye nezinto ezisetyenziswa kula makhonkco maziqinisekise. ukuba i-resistantivity iphantsi, ukwenzela ukuba kuqinisekiswe ukuba i-impedance iyonke yebhodi yesiphaluka iphantsi ukuhlangabezana neemfuno zomgangatho wemveliso kwaye inokusebenza ngokuqhelekileyo.

Okwesithathu, i-tin plating yeebhodi zesekethe ye-pcb yeyona nto ithandwa kakhulu kwiingxaki kwimveliso yebhodi yesekethe yonke, kwaye likhonkco eliphambili elichaphazela i-impedance. Esona siphene sikhulu se-electroless tin coating yi-discoloration elula (kulula ukuba i-oxidized okanye i-deliquescent) kunye nokungahambi kakuhle kwe-solderability, okuya kukhokelela kwi-soldering enzima yebhodi yesekethe, i-impedance ephezulu, ukungahambi kakuhle kombane, okanye ukungazinzi kwebhodi yokusebenza kwebhodi.

4. Kukho ii-transmissions ezahlukeneyo zesignali kwii-conductor zebhodi yesekethe ye-pcb. Xa i-frequency kufuneka inyuswe ukwenzela ukwandisa izinga lokudluliselwa kwayo, ukuba isekethe ngokwayo iyahluka ngenxa yezinto ezifana ne-etching, i-stack thick, ububanzi be-wire, njl., ixabiso le-impedance liya kutshintsha. , Ukuze umqondiso wayo uphazamiseke kwaye ukusebenza kwebhodi yesekethe kuhlaziywe, ngoko ke kuyimfuneko ukulawula ixabiso le-impedance ngaphakathi koluhlu oluthile.