---
title: VGA
updated: 2022-01-12 02:49:03Z
created: 2022-01-08 14:06:18Z
latitude: 1.29820000
longitude: 103.78360000
altitude: 0.0000
---

# MAAM-011100

Broadband Variable Gain Amplifier (VGA) 400MHz-20GHz

75RBM
![1a077f7726eb03a17c40183a73e51522.png](../../../_resources/1a077f7726eb03a17c40183a73e51522.png)
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
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 
![-2V-CTL-driver.png](../../../_resources/-2V-CTL-driver-1.png)
实际输出映射关系
|MCU|	CTL|
|:-:|:-:|
1.6	|0.1	
3.1	|-2.15
tps61040产生±5V电压，供给运放和VGA的偏置 


20200611更新
改为同向驱动，即输入输出同大同小，电压越高增益越大
则传输函数为==y=x-2.5==，电路图为-2v-driver-new.png 
![-2v-driver-new.png](../../../_resources/-2v-driver-new-1.png)
实际输出映射关系
|MCU|CTL|
|:-:|:-:|
0.6|-2.1	
2.6	|0.1
运放需要支持双电源，可选用M2107G-AF5-R 够用、体积小，便宜
调谐灵敏度约为15.5dB/V，参考来源：gain-VC.png 
![gain-VC.png](../../../_resources/gain-VC-1.png)