47 lines
2.2 KiB
Markdown
47 lines
2.2 KiB
Markdown
---
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title: PLL简述
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updated: 2022-01-11 02:09:25Z
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created: 2022-01-10 03:35:59Z
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---
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> 节选自应用笔记《[射频与微波技术实用手册](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E5%BA%94%E7%94%A8%E7%AC%94%E8%AE%B0%5C%E5%B0%84%E9%A2%91%E4%B8%8E%E5%BE%AE%E6%B3%A2%E6%8A%80%E6%9C%AF%E5%AE%9E%E7%94%A8%E6%89%8B%E5%86%8C.pdf "page=127")》P127
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# 集成VCO的PLL
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ADI公司集成VCO的PLL覆盖25MHz到13.6GHz
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表中数据按以下品质因数FOM计算：
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- 整数分频-226dBc/Hz
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- 小数分频-221dBc/Hz
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从表中可以看出
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- [HMC833](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5CADI%5CPLLs%5Chmc833.pdf)可覆盖至6GHz，对标LMX2572
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- [HMC835](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5CADI%5CPLLs%5Chmc835.pdf)相噪不如[HMC830](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5CADI%5CPLLs%5Chmc830.pdf)、[832](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5CADI%5CPLLs%5Chmc832.pdf)、833，==有待实测验证==
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- 小数分频比整数分频相噪差约5-6dB
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# FOM
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FOM=Figure of Merit，[HMC704](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5CADI%5CPLLs%5Chmc704.pdf)的P2、P13页有单独章节进行理论解释
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几款常用PLL的典型FOM值对比如下
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| PLL | Floor FOM<br>INT/FRAC dBc/Hz | Flick FOM<br>dBc/Hz | *notes* |
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| --- | --- | --- | --- |
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| HMC830,832,833,835 | -230/-227 | -128(-268) | |
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| HMC703,704 | -233/-230 | -126(-266) | HiK Mode, Nornal mode is about 3dB lower |
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| [LMX2594](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5Clmx2594.pdf) | -236 | –129 | |
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| [LMX2820](file:///E:%5C%E6%96%87%E6%A1%A3%5C%E6%95%B0%E6%8D%AE%E6%89%8B%E5%86%8C%5Clmx2820.pdf) | -236 | –134 | |
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从表可以看出几款PLL的FOM典型值差异约6dB
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# 鉴相频率
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从 [相噪](../名词解释/相噪.md) 公式可以看出在其它条件不变的情况下鉴相频率是影响相噪的主要因素，Fpd越高，相噪越低，改善$10*log^N$。
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LMX2594/2820最大Fpd为400/300MHz，HMCxxx只有100MHz，故同等条件下相噪会差4-6dB
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