選(xuan)擇振蕩器時需要(yao)考慮哪些因素(su)

選(xuan)擇振蕩器時(shi)需(xu)要(yao)考慮功耗(hao)。分立振蕩器的(de)(de)功耗(hao)主(zhu)要(yao)由反饋放大器的(de)(de)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)流以(yi)及電(dian)(dian)(dian)(dian)(dian)路(lu)內部的(de)(de)電(dian)(dian)(dian)(dian)(dian)容(rong)值所決(jue)定(ding)(ding)。CMOS放大器功耗(hao)與工(gong)(gong)作(zuo)頻(pin)率成正比(bi)，可以(yi)表示為(wei)功率耗(hao)散電(dian)(dian)(dian)(dian)(dian)容(rong)值。比(bi)如，HC04反相器門電(dian)(dian)(dian)(dian)(dian)路(lu)的(de)(de)功率耗(hao)散電(dian)(dian)(dian)(dian)(dian)容(rong)值是90pF。在4MHz、5V電(dian)(dian)(dian)(dian)(dian)源下工(gong)(gong)作(zuo)時(shi)，差(cha)分晶(jing)振原廠(chang)，相當于1.8mA的(de)(de)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)流。再加上20pF的(de)(de)晶(jing)振負載電(dian)(dian)(dian)(dian)(dian)容(rong)，整個(ge)(ge)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)流為(wei)2.2mA。陶瓷諧振槽路(lu)一(yi)般具(ju)有較大的(de)(de)負載電(dian)(dian)(dian)(dian)(dian)容(rong)，相應(ying)地也需(xu)要(yao)更(geng)多(duo)的(de)(de)電(dian)(dian)(dian)(dian)(dian)流。相比(bi)之下，晶(jing)振模(mo)塊一(yi)般需(xu)要(yao)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)流為(wei)10mA ~60mA。硅振蕩器的(de)(de)電(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)流取決(jue)于其類型與功能，范(fan)圍可以(yi)從低頻(pin)（固定(ding)(ding)）器件(jian)的(de)(de)幾(ji)個(ge)(ge)微(wei)安到可編程器件(jian)的(de)(de)幾(ji)個(ge)(ge)毫安。一(yi)種低功率的(de)(de)硅振蕩器，如MAX7375，差(cha)分晶(jing)振生產(chan)廠(chang)家，工(gong)(gong)作(zuo)在4MHz時(shi)只需(xu)不到2mA的(de)(de)電(dian)(dian)(dian)(dian)(dian)流。在特定(ding)(ding)的(de)(de)應(ying)用場合優(you)化時(shi)鐘源需(xu)要(yao)綜合考慮以(yi)下一(yi)些(xie)因素(su)：精度、成本、功耗(hao)以(yi)及環境需(xu)求。

石英晶體(ti)振蕩器(qi)的(de)應用

（1）石(shi)英(ying)鐘(zhong)走(zou)時準、耗電省、為其優點。不論(lun)是老式石(shi)英(ying)鐘(zhong)或是新式多功能石(shi)英(ying)鐘(zhong)都是以石(shi)英(ying)晶體(ti)振(zhen)蕩器為電路，其頻(pin)率精(jing)度決定了電子鐘(zhong)表的走(zou)時精(jing)度；

（2）隨(sui)著電視(shi)技術的發展，近(jin)來彩電多采(cai)用(yong)500kHz或(huo)503 kHz的晶體振(zhen)蕩(dang)器作為行、場電路(lu)的振(zhen)蕩(dang)源(yuan)，經1/3的分(fen)頻得(de)到(dao) 15625Hz的行頻，其穩定性(xing)和可靠性(xing)大為提高。面且晶振(zhen)價格便宜(yi)，更換容易；

（3）在通信系統產(chan)品(pin)中，差分晶(jing)振(zhen)(zhen)，石英晶(jing)體振(zhen)(zhen)蕩器的(de)價值(zhi)得(de)到了更廣泛的(de)體現，同(tong)時也得(de)到了更快(kuai)的(de)發展。許多的(de)石英晶(jing)振(zhen)(zhen)主要應用于通信網(wang)絡、無線數(shu)據傳輸(shu)、高(gao)速數(shu)字數(shu)據傳輸(shu)等(deng)。為客戶提供適用于軍*及石油隨(sui)鉆(zhan)測井(jing)等(deng)惡(e)略環境的(de)225度(du)高(gao)溫(wen)晶(jing)振(zhen)(zhen)，如有需要，歡(huan)迎來(lai)電咨(zi)詢！

不要盲目的選擇晶振

在工作中，差分(fen)晶振(zhen)現(xian)貨，有(you)客(ke)戶(hu)會(hui)盲目選(xuan)型，可(ke)能是(shi)(shi)出于節省(sheng)時(shi)間，也有(you)可(ke)能是(shi)(shi)“過于自信”。例如，有(you)些客(ke)戶(hu)為了省(sheng)事(shi)省(sheng)時(shi)，KHZ晶振(zhen)尺(chi)寸(cun)與MHZ晶振(zhen)尺(chi)寸(cun)采用同一(yi)個尺(chi)寸(cun)。因此在采購的時(shi)候會(hui)出現(xian)一(yi)個尷尬的情況(kuang)，就是(shi)(shi)很常(chang)規(gui)的時(shi)鐘頻(pin)點遇上MHZ的尺(chi)寸(cun)，竟然會(hui)找不(bu)到(dao)貨。當然找不(bu)到(dao)貨，因為根本沒(mei)有(you)這個規(gui)格生產。所以關于客(ke)戶(hu)選(xuan)型階段，選(xuan)擇的晶宇興能助(zhu)您一(yi)臂之力。