Multilayer ceramic capacitors (MLCCs) yog lub npe hu ua " mov ntawm kev lag luam hluav taws xob." Lawv daim ntawv thov toj roob hauv pes tau nthuav dav los ntawm cov neeg siv khoom siv hluav taws xob mus rau 5G kev sib txuas lus hauv paus chaw nres tsheb, automotive electronics, AI servers, aerospace, thiab ntau lwm yam. Txawm li cas los xij, cov xwm txheej sib txawv ntawm daim ntawv thov muaj ntau qhov kev ua tau zoo sib txawv rau MLCCs. Piv txwv li, automotive -qib MLCCs yuav tsum tau tswj kom ruaj khov capacitance tshaj qhov kub ntawm qhov dav ntawm -55℃mus rau +125 degree, thaum cov chips ua tau zoo xws li CPUs, GPUs, thiab HBM, raws li lub zog txuas ntxiv mus, yuav tsum tau MLCCs los muab ntau dua capacitance nyob rau hauv tsawg zog cia thiab ruaj khov zog xa. Cov yam ntxwv tseem ceeb xws li cov yam ntxwv ntawm qhov kub thiab txias, qhov muaj peev xwm ntau, kev ruaj ntseg ntawm cov hluav taws xob, thiab cov yam ntxwv ntawm kev laus yog qhov tseem ceeb rau cov qauv siv lead ua thiab cov polarization mechanism ntawm ceramic dielectric hmoov.
Raws li qhov sib txawv ntawm cov khoom siv hluav taws xob (cov yam ntxwv kub), MLCCs feem ntau muab faib ua ob pawg loj: Class I kub-pab dielectrics thiab Class II siab-permittivity ferroelectric dielectrics. Cov yav tas los nrhiav qhov kub thiab txias thiab poob qis, thaum lub sij hawm tom kawg nrhiav qhov siab dielectric tas li thiab siab capacitance ceev.
Chav Kawm I Temperature -Compensating Dielectrics
Class I dielectrics feem ntau siv TiO₂ ua cov khoom tseem ceeb, uas muab qhov tsis tshua muaj dielectric tsis tu ncua thiab tsis tshua muaj dielectric poob los xyuas kom meej qhov kub thiab txias stability. Ib qho me me ntawm CaTiO₃ lossis SrTiO₃, thiab lwm yam, kuj tau ntxiv los kho qhov kub thiab txias nkhaus thiab ruaj khov microstructure, tsim qhov kub "extended" -compensating ceramic.
Vim tias hom khoom siv dielectric no nyob rau theem paraelectric, tsis muaj ferroelectric domain hloov lossis tsiv teb tsaws, nws cov lus teb dielectric feem ntau yog los ntawm hluav taws xob thiab ionic hloov chaw polarization thiab tsis muaj cov yam ntxwv ntawm cov polarization ntawm ferroelectrics. Yog li ntawd, qhov dielectric tas li ntawm hom dielectric hloov me ntsis nrog qhov kub thiab txias, zaus, DC bias, thiab lub sijhawm, nthuav tawm cov lus teb yuav luag zoo tshaj plaws, qhov kub thiab txias zoo, thiab tsis muaj qhov tshwm sim ntawm kev laus. Piv txwv li, cov hom I dielectric C0G (NP0) muaj qhov kub thiab txias coefficient ntawm 0 ± 30 ppm / degree; nws capacitance hloov me ntsis nrog kub thiab yog yuav luag negligible. Tau kawg, hom dielectric no muaj qhov dielectric tsis tu ncua. Tus txheeb ze dielectric qhov tsis tu ncua ntawm C0G- cov ntaub ntawv hom feem ntau yog nyob nruab nrab ntawm 6 thiab 200, uas txiav txim siab tias Class I MLCCs nyuaj ua kom muaj peev xwm loj. Yog li ntawd, Chav Kawm I dielectric MLCCs tau siv dav hauv cov xwm txheej uas muaj cov kev cai nruj rau qhov tseeb thiab kev ruaj ntseg tab sis kuj tsis tshua muaj peev xwm xav tau:
01 RF thiab Microwave Circuits
Nyob rau hauv siab -frequency scenarios xws li filtering and matching circuits for 5G base station power amplifier modules and millimeter-wave bands (24–100 GHz), tsis tshua muaj kev nkag tsis zoo thiab cov suab nrov tsawg tsawg yuav tsum tau. Class I dielectrics tuaj yeem ua kom muaj kev ruaj ntseg thiab kev ncaj ncees ntawm cov teeb liab kis.
02 Oscillation thiab Timing Circuits
Crystal oscillators, LC resonant circuits, moos circuits, tank capacitors, thiab lwm yam, yuav tsum muaj kev ruaj ntseg siab heev los xyuas kom meej tias oscillation zaus tsis drift nrog ambient kub, ua kom lub sij hawm meej thiab zaus tswj.
03 Siab-Kev Xeem Kawg thiab Cov Khoom Siv Ntsuas
High -cov cuab yeej precision, cov cuab yeej kuaj mob, radar thiab navigation systems, thiab lwm yam, muaj cov kev xav tau siab heev rau kev ntsuas qhov tseeb thiab qhov system stability. Qhov tsis tshua muaj kub drift yam ntxwv ntawm Class I dielectrics tuaj yeem ua tau raws li qhov yuav tsum tau ua ntawm high -kawg precision khoom.
04 Tub Rog thiab Aerospace Electronics
Cov no yuav tsum tau muaj kev ntseeg siab nrog cov parameter sib xws uas khaws cia dhau qhov kub ntawm qhov kub.
Chav Kawm II Siab -Permittivity Ferroelectric Dielectrics
Class II dielectrics yog cov muaj zog ferroelectric ceramics, nws lub ntsiab yog barium titanate (BaTiO₃). Nyob rau hauv chav tsev kub, barium titanate pom ib tug tetragonal ferroelectric qauv thiab muaj spontaneous polarization. Txawm hais tias tsis muaj qhov hluav taws xob sab nraud, cov hluav taws xob dipoles hauv cov siv lead ua muaj qee qhov kev ua haujlwm tsis tu ncua, thiab cov dielectric tas li tuaj yeem ncav cuag 1500. Txawm li cas los xij, ntshiab BaTiO₃ muaj Curie ncov nrog anomalously siab dielectric tas li nyob ze li ntawm 130℃. Ntawm qhov ntsuas kub no, ferroelectric- mus rau - paraelectric structural theem hloov pauv tshwm sim. Ntawm ob sab ntawm Curie taw tes, lub dielectric qhov hloov pauv tsis tu ncua, ua rau muaj peev xwm hloov pauv tau nrog qhov kub thiab txias thiab siv DC voltage, thiab muaj cov nyhuv laus. Yog li ntawd, kev ntsuas xws li tsim cov tub ntxhais- lub plhaub qauv lossis hloov kho doping yog xav tau los tswj Curie kub ntawm BaTiO₃ thiab nthuav dav dielectric{10}} qhov kub thiab txias spectrum.
01 Tsim ib tug tub ntxhais -Shell Structure
Ntawd yog, los ntawm txheej txheej ntawm nano barium titanate hmoov nrog cov khoom sib txawv (xws li Mg, Mn, Y, Dy, thiab lwm yam tsis tshua muaj hauv ntiaj teb), cov nplej uas tsis yog -cov tshuaj muaj pes tsawg leeg yog tsim tom qab sintering. Cov tub ntxhais yog cov ntshiab barium titanate, uas tswj tau siab ferroelectricity thiab muab siab capacitance; lub plhaub yog ib qho doping- hloov kho cov tshuaj uas muaj qhov sib txawv Curie kub thiab cov yam ntxwv ntawm dielectric kub. Thaum kawg, los ntawm kev kho cov tub ntxhais-plhaub ratio, dielectric kev ua tau zoo thiab kub stability yog sib npaug.
02 Doping Hloov Kho
Cov ntsiab lus tsis tshua muaj hauv ntiaj teb (xws li Y, Dy, Ho) thiab qee cov hlau alkali (xws li Sr) tuaj yeem siv rau A-site (Ba-site), B-site (Ti-}site), lossis amphoteric doping los tswj cov qauv lattice, tsim cov neeg pub dawb lossis txais cov txiaj ntsig, thiab hloov cov kev sib cuam tshuam ntawm cov cell parameters. Qhov no optimizes lub dielectric tas li, txo dielectric poob, suppresses thiab broadens lub dielectric ncov, los yog hloov lub Curie kub mus rau qis dua los yog siab dua kub, ua kom lub dielectric tsis tu ncua kuj ruaj khov nyob rau hauv ib tug wider kub ntau yam thiab kev txhim kho kub stability.
Doping Hloov Kho ntawm Barium Titanate
Raws li cov tswv yim sib txawv doping thiab hmoov formulations, Class II dielectrics ntxiv xws li X5R, X7R, Y5V, Z5U, thiab lwm yam.
(1) X5R: X5R- hom MLCCs muaj cov nqi hloov kho qis dua thiab feem ntau vam khom rau kev tsim cov qauv "core-plhaub" kom nthuav dav qhov kub thiab txias -kev ua haujlwm ruaj khov. Qhov kev hloov kho yuav tsum tau ua kom muaj qhov ntsuas kub ntawm ± 15% tshaj qhov kev ua haujlwm kub ntawm -55℃txog 85 degree. Qhov kev khiav hauj lwm qhov kub thiab txias no yog txaus los npog feem ntau cov xwm txheej ntawm pej xeem, yog li nws yog cov qauv tseem ceeb rau cov neeg siv khoom siv hluav taws xob (cov xov tooj ntawm tes, khoos phis tawj).
(2) X7R: Nws cov kev hloov kho mechanism zoo ib yam li X5R, tab sis cov kev cai rau doping precision kuj nruj. Yog li ntawd, nws lub siab kub txwv yog siab dua, thiab nws muaj peev xwm tswj tau qhov kub thiab txias coefficient nyob rau hauv ± 15% tshaj qhov kev khiav hauj lwm kub ntawm -55℃mus rau 125 degree. Nws yog dav siv nyob rau hauv cov computers, automotive electronics, industrial tswj, thiab lwm yam scenarios uas muaj nruab nrab kub stability thiab yuav tsum tau kuj loj capacitance.
(3) Y5V / Z5U: Y5V thiab Z5U hmoov muaj qhov siab tshaj plaws capacitance ntom ntawm Class II dielectric cov ntaub ntawv, tab sis lawv capacitance drifts heev noticeably nrog kub. Ntawm lawv, Y5V muaj kev ua haujlwm kub ntawm -30℃rau +85℃thiab qhov kub thiab txias coefficient ntawm +22%/-82%; Z5U muaj qhov kub thiab txias ua haujlwm ntawm +10℃rau +85℃thiab kub coefficient ntawm +22%/-56%. Lawv tsuas yog siv tau rau hauv buffering thiab lub zog cia scenarios uas yog kiag li insensitive rau capacitance fluctuation thiab aging degradation, thiab nruj me ntsis txwv tsis pub nyob rau hauv lub teeb liab circuits thiab precision tswj loops.