40 lines
1.2 KiB
Markdown
40 lines
1.2 KiB
Markdown
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---
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title: VGA
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updated: 2022-01-12 02:49:03Z
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created: 2022-01-08 14:06:18Z
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latitude: 1.29820000
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longitude: 103.78360000
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altitude: 0.0000
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---
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# MAAM-011100
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Broadband Variable Gain Amplifier (VGA) 400MHz-20GHz
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75RBM
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调谐电压[0,-2]V，MCU的DAC输出电压(0,3.3)，考虑到误差，达不到极限0，3.3V
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优化后传输函数为==y=-1.5x+2.5==，2.5V电压是采用TL431作为基准，电路图为 -2V-CTL-driver.png
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实际输出映射关系
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|MCU| CTL|
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|:-:|:-:|
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1.6 |0.1
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3.1 |-2.15
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tps61040产生±5V电压，供给运放和VGA的偏置
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20200611更新
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改为同向驱动，即输入输出同大同小，电压越高增益越大
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则传输函数为==y=x-2.5==，电路图为-2v-driver-new.png
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实际输出映射关系
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|MCU|CTL|
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0.6|-2.1
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2.6 |0.1
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运放需要支持双电源，可选用M2107G-AF5-R 够用、体积小，便宜
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调谐灵敏度约为15.5dB/V，参考来源：gain-VC.png
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