TRENDS FOR CLOCKING COMPONENTS: SMALLER AND WITH MORE FREQUENCY STABILITY

時(shí)鐘元件的趨勢(shì)：更小和更高的頻率穩(wěn)定性

The size and frequency stability of clocking pruducts influence the dimensions and power consumption of an end device. The developers of battery-operated products in particular require precise and compact frequency generators – an overview of the current state of technology in the oscillating quartz market.

時(shí)鐘產(chǎn)品的尺寸和頻率穩(wěn)定性會(huì)影響終端設(shè)備的尺寸和功耗。電池供電產(chǎn)品的開發(fā)人員尤其需要精確而緊湊的頻率發(fā)生器——這是振蕩石英市場(chǎng)技術(shù)現(xiàn)狀的概述。

Quartz crystals (or just quartz) was developed into practicable quartz for use in radio engineering at the start of the 1920s. Today, we simply can’t do without quartz in our modern, technological lives. Over recent years, there has been a significant transition from large THT (Through-Hole-Technology) and SMD quartz (Surface Mounted Device) in metal housings for miniaturised SMD quartz in ceramic housings. The need for higher-frequency oscillating quartz in smaller housings has been a big driver for this trend. Thanks to technological advances and several innovations in production, it became possible to significantly reduce the structural size of the oscillating quartz without cutbacks on performance or increased costs.

石英晶體（或只是石英）在20世紀(jì)20年代初被開發(fā)成可用于無線電工程的實(shí)用石英。今天，在現(xiàn)代科技生活中，我們離不開石英晶振。近年來，從金屬外殼中的大THT（通孔技術(shù)）和SMD石英（表面安裝器件）到陶瓷外殼中的小型SMD石英已經(jīng)發(fā)生了重大轉(zhuǎn)變。在較小的外殼中需要更高頻率的振蕩石英是這一趨勢(shì)的主要驅(qū)動(dòng)因素。由于技術(shù)進(jìn)步和生產(chǎn)中的幾項(xiàng)創(chuàng)新，在不降低性能或增加成本的情況下，可以顯著減小振蕩石英的結(jié)構(gòu)尺寸。

At the moment, the form factor 3.2 x 2.5 mm is used a lot in all kinds of applications, mainly in connection with resistance optimisation of the quartz for the optimal oscillation behaviour in the defined working temperature ranges and in the frequency range of 8.0 to 64.0 MHz (AT base tone). They can be operated with a drive level of up to 500 µW (in the frequency range from 12.0 to 64.0 MHz). For particularly demanding applications, components with frequency tolerances of up to ±10 ppm and a temperature range of -55 to 125 °C are available.

此時(shí)此刻外形尺寸為3.2x2.5毫米小體積貼片晶振在各種應(yīng)用中大量使用，主要與石英的電阻優(yōu)化有關(guān)，以便在規(guī)定的工作溫度范圍和8.0至64.0MHz(基音)的頻率范圍內(nèi)獲得最佳振蕩性能。它們可以在高達(dá)500W的驅(qū)動(dòng)電平下工作(頻率范圍為12.0至64.0MHz)。對(duì)于要求特別高的應(yīng)用，頻率容差高達(dá)10ppm的元件和溫度范圍為-55至125℃都是可用的。

In past years, the SMD quartz in ceramic housing with the dimensions from 2.5 x 2.0 mm housing (4 pad) to 3.2 x 2.5 mm housing (4 pad) developed in parallel, but never really caught on. If a 3.2 x 2.5 mm housing is too large, you can rely on the high-volume product in 2.0 x 1.6 mm housing (4-pad). This housing type is on trend for very small applications. The quartz design in this form factor is also resistance-optimised and designed for the optimal oscillation behaviour. The developer can use versions with a drive level of up to 400 µW.

過去，陶瓷外殼中的SMD石英的尺寸從2.5x2.0毫米外殼(4個(gè)襯墊)到3.2x2.5毫米外殼(4個(gè)襯墊)，并行開發(fā)，但從未真正流行起來。如果3.2x2.5mm外殼太大，您可以依靠中的高容量產(chǎn)品2.0x1.6毫米外殼(4片)。這種外殼類型是非常小的應(yīng)用的趨勢(shì)。這種外形的石英設(shè)計(jì)也經(jīng)過電阻優(yōu)化，設(shè)計(jì)用于最佳振蕩行為。開發(fā)者可以使用驅(qū)動(dòng)電平高達(dá)400 W的版本。

The trend towards smaller housings and a greater frequency stability is also evident in the as well. The smallest version with the dimensions 1.2 x 1.0 mm is just about to be released. 32.768 KHz quartz in 3.2 x 1.5 mm housing and 2.0 x 1.2 mm with reduced resistance is seen a great deal now in end devices. Low-resistance quartz with 32.768 kHz and also the standard versions are available on the quartz market with load capacities from 4 to 12.5 pF in the temperature range from -40 to +125 °C. The developer can select between two frequency tolerances at +25 °C: ±10 ppm (optional) or ±20 ppm (standard).

外殼更小、頻率穩(wěn)定性更高的趨勢(shì)在中也很明顯。尺寸為1.2x1.0mm的最小版本即將發(fā)布。32.768千赫石英在3.2x1.5mm外殼和2.0x1.2mm外殼中，電阻降低，現(xiàn)在在終端設(shè)備中很常見。石英市場(chǎng)上提供32.768 kHz的低電阻石英和標(biāo)準(zhǔn)版本，負(fù)載能力為4至12.5 pF，溫度范圍為-40至+125°C。開發(fā)人員可以在+25°C時(shí)選擇兩種頻率容差:10 ppm(可選)或20 ppm(標(biāo)準(zhǔn))。

More and more IC manufacturers are basing their work on SMD quartz with integrated thermistors, for example in a 2.0x1.6 mm ceramic housing. This quartz is used more and more in battery-operated communications products and replaces power-consuming (up to 2 mA) temperature-compensated quartz oscillators (TCXO).

越來越多的IC制造商將其工作基于集成熱敏電阻的SMD石英，例如2.0x1.6mm陶瓷外殼。這種石英越來越多地用于電池供電的通信產(chǎn)品，并取代了高功耗(高達(dá)2 mA)的溫度補(bǔ)償晶振(TCXO)。

It may therefore be concluded that in recent years, things that seemed impossible have occurred in the development of quartz. Progress was made in the miniaturisation of housing sizes without a loss in performance or increase in cost and the technological advances of the electronics sector were used to support getting more and more innovative solutions in product design ready for the market. The result is an ever greater frequency stability with housing sizes that are getting smaller and smaller.

因此可以得出這樣的結(jié)論：近年來，在石英的發(fā)展過程中，似乎不可能的事情發(fā)生了。在不損失性能或增加成本的情況下，在外殼尺寸小型化方面取得了進(jìn)展，電子行業(yè)的技術(shù)進(jìn)步用于支持越來越多的創(chuàng)新產(chǎn)品設(shè)計(jì)解決方案投入市場(chǎng)。結(jié)果是，隨著外殼尺寸越來越小，頻率穩(wěn)定性越來越高。

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