Crystal oscillator yog tus yuam sij hauv digital circuit tsim, feem ntau hauv kev tsim hluav taws xob, siv lead ua oscillator yog siv los ua lub plawv ntawm cov digital circuit, tag nrho cov kev ua haujlwm ntawm digital circuit yog sib cais los ntawm lub moos teeb liab, thiab tsuas yog siv lead ua oscillator yog lub pob tseem ceeb. uas ncaj qha tswj qhov qub pib ntawm tag nrho cov kab ke, nws tuaj yeem hais tau tias yog tias muaj cov qauv siv hluav taws xob digital tuaj yeem pom cov siv lead ua oscillator.
I. Crystal oscillator yog dab tsi?
Crystal oscillator feem ntau yog hais txog ob hom quartz siv lead ua oscillator thiab quartz siv lead ua resonator, thiab tuaj yeem hu ncaj qha hu ua crystal oscillator. Ob leeg yog tsim los siv cov nyhuv piezoelectric ntawm quartz siv lead ua.
Cov siv lead ua oscillator ua haujlwm zoo li no: thaum lub tshuab hluav taws xob siv rau ob lub tshuab hluav taws xob ntawm cov siv lead ua, cov siv lead ua yuav ua rau cov neeg kho tshuab deformation, thiab ntawm qhov tsis sib xws, yog tias siv tshuab siab siv rau ob qhov kawg ntawm cov siv lead ua, cov siv lead ua yuav tsim tawm. ib qho hluav taws xob teb. Qhov tshwm sim no yog thim rov qab, yog li siv cov yam ntxwv ntawm cov siv lead ua no, ntxiv cov hluav taws xob hloov pauv mus rau ob qho kawg ntawm cov siv lead ua, cov nti yuav tsim cov tshuab kev co, thiab tib lub sijhawm tsim cov hluav taws xob sib hloov. Txawm li cas los xij, qhov kev vibration thiab hluav taws xob no tsim los ntawm cov siv lead ua feem ntau me me, tab sis ntev npaum li nws nyob ntawm qee zaus, qhov amplitude yuav nce ntxiv, zoo ib yam li LC voj resonance uas peb cov neeg tsim hluav taws xob feem ntau pom.
II. Kev faib tawm ntawm crystal oscillations (active thiab passive)
① Passive siv lead ua oscillator
Passive siv lead ua yog siv lead ua, feem ntau yog 2-pin non-polar ntaus ntawv (qee qhov siv lead ua tsis muaj tus pin ruaj tsis muaj polarity).
Passive siv lead ua oscillator feem ntau yuav tsum tau cia siab rau lub moos Circuit Court tsim los ntawm lub load capacitor los tsim cov teeb liab oscillating (sine yoj teeb liab).
② Siv lead ua oscillator
Ib qho siv lead ua oscillator yog oscillator, feem ntau muaj 4 tus pins. Cov siv lead ua oscillator tsis tas yuav tsum tau CPU lub oscillator sab hauv los tsim cov teeb liab square. Lub active siv lead ua fais fab mov generates ib lub moos teeb liab.
Lub teeb liab ntawm active siv lead ua oscillator yog qhov ruaj khov, qhov zoo yog qhov zoo dua, thiab kev sib txuas hom yog qhov yooj yim, qhov tseeb yuam kev me dua li ntawm passive siv lead ua oscillator, thiab tus nqi kim dua li passive crystal oscillator.
III. Basic parameters ntawm crystal oscillator
Cov yam ntxwv tseem ceeb ntawm cov siv lead ua oscillator yog: kev khiav hauj lwm kub, precision tus nqi, txuam capacitance, pob daim ntawv, core zaus thiab hais txog.
Cov tub ntxhais zaus ntawm cov siv lead ua oscillator: Kev xaiv ntawm cov siv lead ua dav dav nyob ntawm qhov yuav tsum tau muaj ntawm cov khoom siv zaus, xws li MCU feem ntau yog ntau yam, feem ntau yog los ntawm 4M mus rau kaum ob ntawm M.
Crystal vibration precision: qhov tseeb ntawm cov siv lead ua vibration feem ntau yog ± 5PPM, ± 10PPM, ± 20PPM, ± 50PPM, thiab lwm yam., high-precision moos chips feem ntau nyob rau hauv ± 5PPM, thiab kev siv dav dav yuav xaiv txog ± 20PPM.
Qhov sib txuam capacitance ntawm cov siv lead ua oscillator: feem ntau yog los ntawm kev kho tus nqi ntawm qhov sib txuam capacitance, cov tub ntxhais zaus ntawm cov siv lead ua oscillator tuaj yeem hloov pauv, thiab tam sim no, txoj kev no yog siv los kho cov high-precision siv lead ua oscillator.
Nyob rau hauv Circuit Court system, kev kub ceev moos teeb liab kab muaj qhov tseem ceeb tshaj plaws. Lub moos kab yog lub teeb liab rhiab heev, thiab qhov zaus ntau dua, txoj kab luv luv yuav tsum tau ua kom ntseeg tau tias qhov cuam tshuam ntawm lub teeb liab yog qhov tsawg.
Tam sim no nyob rau hauv ntau lub voj voog, siv lead ua moos zaus ntawm lub kaw lus yog siab heev, yog li lub zog ntawm kev cuam tshuam nrog kev sib haum xeeb kuj muaj zog, harmonics yuav muab tau los ntawm cov tswv yim thiab tso tawm ob kab, tab sis kuj los ntawm qhov chaw hluav taws xob, uas kuj ua rau. Yog hais tias PCB layout ntawm lub crystal oscillator tsis tsim nyog, nws yuav yooj yim ua rau ib tug muaj zog stray teeb meem, thiab ib zaug tsim, nws yog ib qho nyuaj rau kev daws los ntawm lwm txoj kev. Yog li ntawd, nws yog ib qho tseem ceeb heev rau cov siv lead ua oscillator thiab CLK teeb liab kab layout thaum lub PCB board tau nteg tawm.