Isano iri hagati yumutwaro wo hanze nu mutwaro wa Crystal

Muburyo bwa elegitoronike, oscillator ya kristu nimwe mumasoko asanzwe. Kugirango utangire neza kandi uhamye imikorere ya kristal oscillator, ubushobozi bwo gutwara ibintu hanze mumuzunguruko bigomba kuba byateguwe neza ukurikije ubushobozi bwacyo (CL). Guhuza ubushobozi bwa capacitor bidakwiye birashobora gutera ingorane mukuzunguruka, kwiyongera kwinshuro, ndetse na sisitemu idahungabana.

Iyi ngingo izatanga isesengura rirambuye kubisobanuro bya kristal oscillator yimitwaro yubushobozi, uburyo bwo kubara kubushobozi bwo hanze, hamwe nibitekerezo bifatika mugushushanya.

Ⅰ. Ni ubuhe bushobozi bwo gutwara ibintu (CL) bwa oscillator ya kristu?

Abakora Crystal mubusanzwe bagaragaza ubushobozi bwumutwaro (CL) mumibare yamakuru, nka 18pF, 20pF, 12pF, nibindi.

Muyandi magambo, oscillator ya kristu irashobora gusohora inshuro nyayo mugihe ubushobozi bwumutwaro uhwanye na CL.

Ⅱ. Nigute ubushobozi bwo gutwara imizigo yo hanze bugira ingaruka kubushobozi bwumutwaro?

Inzira isanzwe ya kristu oscillator ifata ifishi ikurikira:

C1 na C2 nubushobozi bubiri bwo hanze buhujwe nubutaka (mubisanzwe ubushobozi bwa SMD);

Imirongo ibiri ya XTAL ihujwe na pin ebyiri za kristu oscillator;

Mu myitozo, ubushobozi buringaniye bwa capacitance CL ya kristu igenwa na C1 na C2 murukurikirane, ihujwe na parasitike capacitance Cp yatangijwe na PCB hamwe na pack.

Ⅲ. Imibare yo Kubara: Nigute Twamenya Agaciro ka Capacitor yo hanze ishingiye kuri CL?

Inzira yubushobozi bungana (CL) nuburyo bukurikira:

Aho:

C1, C2: Ubushobozi bwo hanze buhujwe n'ubutaka;

Cp: ​​Ubushobozi bwa parasitike bwatangijwe na PCB, gupakira, nibindi (mubisanzwe 2pF kugeza 5pF, birashobora kugereranywa ukoresheje kwigana cyangwa uburambe);

CL: Nominal load capacitance yerekanwe muri kristu oscillator datasheet.

【Urugero】

Dufate ko ibisobanuro bya kristu ari CL=18 pF, hamwe na PCB parasitike ya capacitance Cp ≈ 5pF. Kubara indangagaciro zikwiye kuri C1 na C2:

Ubwa mbere, usimbuze indangagaciro muri formula:

Dufashe C 1=C 2=C, formula yoroshye kuri:

Igisubizo ni:

✅ Kubwibyo, ibyifuzo bisabwa hanze ni: C 1=C 2 =27pF (Agaciro gasanzwe).

Ⅳ. Kuki bidahuye nubushobozi bwo hanze butera ibibazo?

Gutandukana inshuro: Niba ubushobozi bwo hanze ari buto cyane cyangwa bunini cyane, kristu izatandukana numurongo wizina ryayo, bitera amakosa yisaha ya sisitemu.

Tangira - hejuru ingorane cyangwa guhungabana: Kurenza urugero bigabanya inyungu, bishobora gutera kristu kunanirwa gutangira cyangwa guhura na jitter ya jitter.

Kongera ingufu z'amashanyarazi: Gupakira bidakwiye biganisha ku gukoresha ingufu nyinshi muri sisitemu ya oscillator.

Kwiyongera kwa EMI: Ihungabana ridahindagurika rishobora kubyara inshuro zidasanzwe, bigira ingaruka kuri sisitemu ya electromagnetic ihuza (EMC).

Ⅴ. Gushushanya Ibyifuzo hamwe nubwubatsi

Witondere witonze kristu oscillator datasheet

Menya agaciro ka CL.

Sobanukirwa na topologiya isabwa.

Reba niba urutonde rwindangagaciro zo hanze zisabwa.

2. Reba ibidukikije byukuri

Gereranya Cp ukoresheje kwigana PCB cyangwa uburambe.

Kumurongo muremure - umuvuduko cyangwa amasaha asobanutse (urugero, sisitemu yitumanaho, inshuro nkuru ya MCU> 100MHz), birasabwa kubara neza cyangwa kugerageza.

3. Koresha ubushobozi bwa simmetrike

Mubisanzwe birasabwa ko C 1=C2 kugirango ushire hagati yumurongo no kuringaniza urusaku.

Igishushanyo cya Asimmetrical kirashobora kandi gukoreshwa kubisabwa bidasanzwe bihuye.

4. Koresha ubushobozi bwa SMD murwego rwo gukemura

Ubushakashatsi hamwe nubushobozi bwa SMD (urugero, 10pF, 15pF, 22pF, 27pF, nibindi) kugirango ubone ibikwiye;

Reba ibisohoka bihamye hamwe ninshuro zukuri ukoresheje isesengura rya sprifike cyangwa oscilloscope.

6,BisanzweIbibazo

Umwanzuro

Igishushanyo mbonera cyimitwaro yo hanze ya kristu oscillator ni ntoya ariko irambuye igira ingaruka itaziguye kandi ihamye ya sisitemu yisaha. Gusobanukirwa isano iri hagati ya CL na C1 / C2, no guhindura ibipimo bishingiye kubushobozi bwa PCB parasitike ya PCB, ni urufunguzo rwo kugera ku ihindagurika ryizewe hamwe ninshuro zuzuye.

Muri sisitemu yo hejuru - yihuta ya sisitemu ya digitale, ibikoresho byitumanaho, cyangwa sisitemu ifite amasaha asabwa cyane, guhitamo neza no guhuza ubushobozi bwimitwaro ya kristu oscillator ni umurimo wubwubatsi ugomba gufatanwa uburemere.

HCIifite laboratoire yabigize umwuga hamwe nitsinda ryabashoramari basaba bafite uburambe bwimyaka 20, batanga serivisi zubuhanga bwo guhuza no gupima abakiriya. Niba hari ibyo ukeneye muriki kibazo, nyamuneka hamagara kugurisha cyangwa abakozi bacu tekinike.