Hauv cov txheej txheem tsim PCB, qee tus engineers tsis xav nteg tooj liab rau tag nrho cov txheej hauv qab kom txuag tau sijhawm.Qhov no puas yog?Puas yog PCB yuav tsum tau tooj liab plated?
Ua ntej tshaj plaws, peb yuav tsum ua kom meej meej: hauv qab tooj liab plating yog qhov zoo thiab tsim nyog rau PCB, tab sis cov tooj liab plating ntawm tag nrho lub rooj tsavxwm yuav tsum ua tau raws li qee yam kev mob.
Cov txiaj ntsig ntawm hauv qab tooj liab plating
1. Los ntawm qhov kev xav ntawm EMC, tag nrho cov saum npoo ntawm cov txheej hauv qab yog them nrog tooj liab, uas muab kev tiv thaiv kev tiv thaiv ntxiv thiab kev tawm suab nrov rau cov teeb liab sab hauv thiab sab hauv.Nyob rau tib lub sijhawm, nws kuj muaj qee qhov thaiv kev tiv thaiv rau cov khoom siv hauv qab thiab cov teeb liab.
2. Los ntawm qhov kev xav ntawm cov cua kub dissipation, vim qhov tam sim no nce hauv PCB board ntom ntom, BGA lub ntsiab nti tseem yuav tsum tau xav txog cov teeb meem kub dissipation ntau dua.Tag nrho lub rooj tsav xwm hauv Circuit Court yog grounded nrog tooj liab los txhim kho cov cua kub dissipation peev ntawm PCB.
3. Los ntawm cov txheej txheem ntawm kev pom, tag nrho lub rooj tsavxwm yog grounded nrog tooj liab ua rau lub rooj tsavxwm PCB sib npaug.PCB dabtsi yog khoov thiab warping yuav tsum zam thaum PCB ua thiab nias.Nyob rau tib lub sijhawm, kev ntxhov siab los ntawm PCB reflow soldering yuav tsis tshwm sim los ntawm cov ntawv nyiaj tsis sib xws.PCB warpage.
Ceeb Toom: Rau ob-txheej boards, tooj liab txheej yuav tsum tau
Ntawm qhov tod tes, vim tias lub rooj tsav xwm ob txheej tsis muaj lub dav hlau ua tiav, cov av hauv av tuaj yeem muab txoj hauv kev rov qab los, thiab tseem tuaj yeem siv los ua coplanar siv los ua kom tiav lub hom phiaj ntawm kev tswj impedance.Peb feem ntau tuaj yeem muab cov dav hlau hauv av rau hauv qab txheej, thiab tom qab ntawd muab cov khoom tseem ceeb thiab cov kab hluav taws xob thiab cov kab teeb liab rau saum txheej.Rau siab impedance circuits, analog circuits (analog-to-digital conversion circuits, switch-mode power conversion circuits), tooj liab plating yog tus cwj pwm zoo.
Cov xwm txheej rau tooj liab plating rau hauv qab
Txawm hais tias txheej hauv qab ntawm tooj liab yog qhov haum rau PCB, nws tseem yuav tsum tau ua kom tau raws li qee qhov xwm txheej:
1. Pw kom ntau li ntau tau nyob rau tib lub sijhawm, tsis txhob npog tag nrho ib zaug, zam cov tawv nqaij tooj liab los ntawm kev tawg, thiab ntxiv los ntawm qhov rau hauv av txheej ntawm thaj tsam tooj liab.
Yog vim li cas: Cov txheej tooj liab ntawm cov txheej txheej saum npoo yuav tsum tau tawg thiab rhuav tshem los ntawm cov khoom siv thiab cov kab teeb liab ntawm txheej txheej.Yog tias cov ntawv ci tooj liab tsis zoo (tshwj xeeb tshaj yog cov ntawv nyias nyias thiab ntev tooj liab tawg), nws yuav dhau los ua tus kav hlau txais xov thiab ua rau muaj teeb meem EMI.
2. Xav txog qhov thermal tshuav ntawm cov pob me me, tshwj xeeb tshaj yog cov pob me me, xws li 0402 0603, kom tsis txhob muaj qhov cuam tshuam loj heev.
Yog vim li cas: Yog hais tias tag nrho cov Circuit Court board yog tooj liab-plated, tooj liab ntawm cov tivthaiv pins yuav tag nrho txuas nrog tooj liab, uas yuav ua rau lub tshav kub dissipate sai heev, uas yuav ua rau muaj teeb meem nyob rau hauv desoldering thiab rework.
3. Lub grounding ntawm tag nrho cov PCB Circuit Court board yog nyiam dua nruam grounding.Qhov kev ncua deb ntawm av mus rau lub teeb liab yuav tsum tau tswj kom tsis txhob muaj kev cuam tshuam ntawm impedance ntawm cov kab sib kis.
Yog vim li cas: Daim ntawv tooj liab nyob ze rau hauv av yuav hloov qhov impedance ntawm microstrip kis kab, thiab daim ntawv tooj liab tsis tu ncua kuj yuav muaj kev cuam tshuam tsis zoo rau impedance discontinuity ntawm cov kab sib kis.
4. Qee qhov xwm txheej tshwj xeeb nyob ntawm daim ntawv thov scenario.PCB tsim yuav tsum tsis yog tus qauv tsim, tab sis yuav tsum tau hnyav thiab ua ke nrog ntau yam kev xav.
Yog vim li cas: Ntxiv nrog rau cov teeb liab rhiab heev uas yuav tsum tau ua hauv av, yog tias muaj ntau cov kab hluav taws xob siab ceev thiab cov khoom siv, ntau qhov me me thiab ntev tooj liab tawg yuav raug tsim, thiab cov xov hlau txuas tau nruj.Nws yog ib qho tsim nyog kom tsis txhob muaj ntau qhov tooj liab qhov ntawm qhov chaw raws li qhov ua tau los txuas rau hauv av txheej.Cov txheej txheej saum npoo tuaj yeem xaiv ua lwm yam tshaj li tooj liab.