Kutheni le nto i-crystal oscillator ingabekwa kumda webhodi yePCB?

I-Crystal oscillator isitshixo kuyilo lwesekethe yedijithali, ngokuqhelekileyo kuyilo lwesekethe, i-crystal oscillator isetyenziswa njengentliziyo yesekethe yedijithali, wonke umsebenzi wesekethe yedijithali ayinakwahlulwa kwisignali yewotshi, kwaye nje i-crystal oscillator iqhosha eliphambili. elawula ngokuthe ngqo ukuqala okuqhelekileyo kwenkqubo yonke, kunokuthiwa ukuba kukho uyilo lwesekethe yedijithali inokubona i-crystal oscillator.

I. Yintoni i-crystal oscillator?

I-Crystal oscillator ngokubanzi ibhekisa kwiindidi ezimbini ze-quartz crystal oscillator kunye ne-quartz crystal resonator, kwaye inokubizwa ngokuthe ngqo yi-crystal oscillator.Zombini zenziwe ngokusebenzisa i-piezoelectric effect ye-quartz crystals.

I-crystal oscillator isebenza ngolu hlobo: xa intsimi yombane isetyenziselwa i-electrode ezimbini ze-crystal, i-crystal iya kuba ne-deformation ye-mechanical deformation, kwaye ngokuchaseneyo, ukuba uxinzelelo lomatshini lusetyenziswa kwiiphelo ezimbini ze-crystal, i-crystal iya kuvelisa. indawo yombane.Esi siganeko siyabuyiselwa umva, ngoko ke ukusebenzisa olu phawu lwekristale, ukongeza umbane otshintshanayo kuzo zombini iziphelo zekristale, i-chip iya kuvelisa ukungcangcazela komatshini, kwaye kwangaxeshanye ivelise imimandla yombane etshintshanayo.Nangona kunjalo, le vibration kunye nentsimi yombane eveliswa yi-crystal ngokuqhelekileyo incinci, kodwa ngokude nje ikwi-frequency ethile, i-amplitude iya kwandiswa kakhulu, ifana ne-LC loop resonance thina abayili beesekethe esihlala siyibona.

II.Ukuhlelwa kwekristale oscillations (esebenzayo kunye ne-passive)

① I-oscillator yekristale engabonakaliyo

I-crystal engabonakaliyo yikristale, ngokubanzi i-2-pin i-non-polar device (enye i-crystal passive ine-pin esisigxina engenawo polarity).

I-passive crystal oscillator ngokubanzi idinga ukuthembela kwisekethe yewotshi eyenziwe ngumthwalo we-capacitor ukuvelisa umqondiso we-oscillating (umqondiso we-sine wave).

② I-oscillator yekristale esebenzayo

I-crystal oscillator esebenzayo i-oscillator, ngokuqhelekileyo inezikhonkwane ezi-4.I-crystal oscillator esebenzayo ayifuni i-oscillator yangaphakathi ye-CPU ukuvelisa isiginali ye-square-wave.Umbane osebenzayo wekristale uvelisa uphawu lwewotshi.

Umqondiso we-crystal oscillator esebenzayo uzinzile, umgangatho ungcono, kwaye imodi yokudibanisa ilula, impazamo echanekileyo incinci kune-oscillator ye-crystal oscillator, kwaye ixabiso libiza kakhulu kune-crystal oscillator.

III.Iiparamitha ezisisiseko ze-crystal oscillator

Iiparameters ezisisiseko ze-crystal oscillator jikelele zezi: ukushisa okusebenzayo, ixabiso elichanekileyo, i-capacitance ehambelanayo, ifom yephakheji, i-core frequency kunye nokunye.

Eyona frequency yecrystal oscillator: Ukukhethwa kwefrikhwensi yekristale ngokubanzi kuxhomekeke kwiimfuno zamacandelo amaza, njenge-MCU ngokubanzi luluhlu, uninzi lwayo lusuka kwi-4M ukuya kwishumi elinesibini leM.

Ukuchaneka kwe-Crystal vibration: ukuchaneka kwe-crystal vibration ngokuqhelekileyo ± 5PPM, ± 10PPM, ± 20PPM, ± 50PPM, njl., iichips zewashi ezichanekileyo ngokuqhelekileyo zingaphakathi kwe-± 5PPM, kwaye ukusetyenziswa ngokubanzi kuya kukhetha malunga ne-± 20PPM.

I-capacitance ehambelanayo ye-crystal oscillator: ngokuqhelekileyo ngokulungelelanisa ixabiso le-capacitance ehambelanayo, i-core frequency ye-crystal oscillator ingatshintshwa, kwaye ngoku, le ndlela isetyenziselwa ukulungelelanisa i-crystal oscillator echanekileyo.

Kwinkqubo yesiphaluka, umgca wesignali yewotshi yesantya esiphezulu unokubaluleka okuphezulu.Umgca wewashi ngumqondiso obuthathaka, kwaye i-frequency ephezulu, i-short line iyadingeka ukuze kuqinisekiswe ukuba ukuphazamiseka kwesiginali kuncinci.

Ngoku kwiisekethe ezininzi, i-crystal clock frequency yenkqubo iphezulu kakhulu, ngoko ke amandla okuphazamisa i-harmonics nawo anamandla, i-harmonics iya kuthathwa kwigalelo kunye nemveliso yemigca emibini, kodwa kwakhona kwi-radiation space, ekhokelela kwakhona ukuba i-PCB layout ye-crystal oscillator ayikho ngqiqweni, iya kubangela ngokulula ingxaki eyomeleleyo yemitha yemitha, kwaye emva kokuba ivelisiwe, kunzima ukusombulula ngezinye iindlela.Ngoko ke, kubaluleke kakhulu kwi-crystal oscillator kunye ne-CLK yomgca wesignali yesignali xa ibhodi ye-PCB ibekwe.