MOSFETs ua haujlwm li cas

Lub hauv paus ntsiab lus ua haujlwm ntawm MOSFET feem ntau yog ua raws li nws cov yam ntxwv tshwj xeeb thiab cov teebmeem hluav taws xob. Cov hauv qab no yog cov lus piav qhia ntxaws txog yuav ua li cas MOSFETs ua haujlwm:

 

I. Basic qauv ntawm MOSFET

Lub MOSFET feem ntau muaj lub rooj vag (G), qhov chaw (S), lub qhov tso dej (D), thiab lub substrate (B, qee zaum txuas nrog lub hauv paus los tsim peb lub davhlau ya nyob twg). Hauv N-channel txhim kho MOSFETs, lub substrate feem ntau yog cov khoom siv tsawg-doped P-hom silicon uas ob qhov chaw ua haujlwm N-hom yog tsim los ua qhov chaw thiab ntws, raws li. Qhov saum npoo ntawm P-hom substrate yog them nrog ib tug nyias oxide zaj duab xis (silicon dioxide) raws li ib tug insulating txheej, thiab ib tug electrode yog kos raws li lub rooj vag. Cov qauv no ua rau lub rooj vag insulated los ntawm P-hom semiconductor substrate, ntws thiab qhov chaw, thiab yog li tseem hu ua insulated-gate field effect tube.

II. Txoj cai ntawm kev ua haujlwm

MOSFETs ua haujlwm los ntawm kev siv lub rooj vag qhov hluav taws xob (VGS) los tswj cov dej ntws tam sim no (ID). Tshwj xeeb, thaum siv qhov zoo ntawm lub qhov rooj qhov hluav taws xob, VGS, ntau dua li xoom, qhov hluav taws xob sab saud thiab qis qis yuav tshwm sim ntawm oxide txheej hauv qab lub rooj vag. Qhov chaw hluav taws xob no nyiam cov hluav taws xob dawb hauv P-thaj chaw, ua rau lawv sib sau hauv qab txheej oxide, thaum rov ua qhov hauv P-region. Raws li VGS nce, lub zog ntawm cov hluav taws xob hluav taws xob nce thiab cov concentration ntawm cov khoom siv hluav taws xob dawb tau nce. Thaum VGS nce mus txog qhov pib voltage (VT), qhov siab ntawm cov hluav taws xob dawb sib sau ua ke hauv cheeb tsam yog qhov loj txaus los tsim ib cheeb tsam N-hom tshiab (N-channel), uas ua zoo li tus choj txuas cov dej ntws thiab qhov chaw. Lub sijhawm no, yog tias muaj qee yam tsav tsheb voltage (VDS) nyob nruab nrab ntawm qhov ntws thiab qhov chaw, qhov ntws tam sim no ID pib ntws.

III. Tsim thiab hloov kev coj ua channel

Kev tsim cov channel ua haujlwm yog tus yuam sij rau kev ua haujlwm ntawm MOSFET. Thaum VGS ntau dua VT, cov channel ua tau tsim thiab qhov ntws tam sim no ID cuam tshuam los ntawm ob qho tib si VGS thiab VDS.VGS cuam tshuam ID los ntawm kev tswj qhov dav thiab cov duab ntawm cov channel, thaum VDS cuam tshuam rau ID ncaj qha raws li kev tsav tsheb. Nws yog ib qho tseem ceeb uas yuav tsum nco ntsoov tias yog tias qhov kev coj ua channel tsis raug tsim (piv txwv li, VGS tsawg dua VT), ces txawm tias VDS tam sim no, tus ID ntws tam sim no tsis tshwm sim.

IV. Cov yam ntxwv ntawm MOSFETs

High input impedance:Lub input impedance ntawm MOSFET yog siab heev, nyob ze rau infinity, vim hais tias muaj ib tug insulating txheej ntawm lub rooj vag thiab lub hauv paus-drain cheeb tsam thiab tsuas yog ib tug tsis muaj zog rooj vag tam sim no.

Tsawg tso zis impedance:MOSFETs yog cov khoom siv hluav taws xob tswj hluav taws xob uas lub hauv paus-drain tam sim no tuaj yeem hloov pauv nrog cov input voltage, yog li lawv cov zis impedance me me.

Tsis tu ncua ntws:Thaum ua haujlwm hauv cheeb tsam saturation, tam sim no ntawm MOSFET zoo li tsis muaj kev cuam tshuam los ntawm kev hloov pauv hauv qhov hluav taws xob-drain voltage, muab tam sim no zoo heev.

 

Zoo kub stability:Cov MOSFETs muaj qhov kub thiab txias ntawm -55 ° C txog + 150 ° C.

V. Kev siv thiab kev faib tawm

MOSFETs tau siv dav hauv digital circuits, analog circuits, hluav taws xob circuits thiab lwm yam. Raws li hom kev ua haujlwm, MOSFETs tuaj yeem muab faib ua hom kev txhim kho thiab depletion; Raws li hom kev coj channel, lawv tuaj yeem faib ua N-channel thiab P-channel. Cov sib txawv ntawm MOSFETs no muaj lawv tus kheej zoo nyob rau hauv kev sib txawv daim ntawv thov scenarios.

Hauv cov ntsiab lus, lub hauv paus ntsiab lus ua haujlwm ntawm MOSFET yog los tswj kev tsim thiab hloov pauv ntawm cov channel ua haujlwm los ntawm lub qhov rooj qhov hluav taws xob, uas nyob rau hauv lem tswj cov ntws ntws tam sim no. Nws cov input impedance siab, tsis tshua muaj tso zis impedance, tsis tu ncua tam sim no thiab kub stability ua MOSFETs yog ib qho tseem ceeb ntawm cov hluav taws xob circuits.