高精度的SMD振蕩器深受智能家居應(yīng)用的追棒ECS-8FMX-080-T，在比較石英和 MEMS 的頻率與溫度穩(wěn)定性時。您會看到基于石英貼片晶振的振蕩器遵循 AT 晶體的連續(xù)三次曲線，并在 -40°C ~ +85°C 范圍內(nèi)達(dá)到 ±25 ppm，這對于大多數(shù)應(yīng)用來說已經(jīng)足夠了。

查看 MEMS 圖，它似乎具有更好的頻率與溫度特性，但如果仔細(xì)觀察，您會發(fā)現(xiàn)該圖顯示了在調(diào)整 PLL 分頻比以補償溫度變化時引起的頻率跳躍。這會導(dǎo)致顯著的頻率跳躍，以補償 MEMS 諧振器的顯著頻率漂移（30 ppm/°C 或 3750 ppm -40°C ~ +85°C）

石英在溫度范圍內(nèi)比 MEMS 更穩(wěn)定，并提供高“Q”性能。基于石英的振蕩器不需要采用溫度補償來在所需溫度范圍內(nèi)保持低至 ±10 ppm 的穩(wěn)定性。如果需要更好的穩(wěn)定性，您可以向石英晶體振蕩器添加溫度補償，并在整個溫度范圍內(nèi)獲得低至 0.5 ppm 的穩(wěn)定性。

When comparing the Frequency vs. Temperature stability of quartz and MEMS. You see that the quartz-based oscillator follows the continuous cubic curve of an AT crystal and achieves ±25 ppm from -40°C ~ +85°C, which is good enough for most applications.

Looking at the MEMS plot it appears to have better frequency vs. temperature characteristics, but if you look closely you can see that the plot shows frequency jumps caused when the PLL division ratio is adjusted to compensate for changes in temperature. This causes significant Frequency jumps in order to compensate for the considerable frequency drift of the MEMS resonator (30 ppm/°C or 3750 ppm -40°C ~ +85°C)

Quartz is much more stable over temperature than MEMS and offers high “Q” performance. The quartz-based oscillator does not need to employ temperature compensation to maintain stabilities as low as ±10 ppm over the required temperature range. If better stabilities are required, you can add temperature compensation to a quartz oscillator and get stabilities as low as 0.5 ppm over temperature.

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