ADS仿真碰到一个问题！急！求教！~

netshell

下图是我设计的差分放大器电路原理图，在ADS里进行交流仿真。这是我用ADS仿真的结果，中间TL+,TL-这2根线的电压差值最高时才1.9V，可我的信号源是1V的呀，请问这是怎么回事呢？正常吗？谢谢！！！

hezudao

Have you ever designed some circuits before? Do you know how to analyze gain of your circuit?
check current in current source and you can already estimate gm and then the gain

netshell

回复 2# hezudao


    我还是不太明白 那就是说要先求出gm然后算出增益？

   但我现在是用ADS工具进行仿真 直接看结果应该就是了吧？


我这个是单端输入差分输出的差分放大器，[ (TL+) -(TL-) ] /RFin 不就是差模增益吗？

请指教！

ckkckk

仿增益哪有用这么大信号仿的啊

hezudao

回复 4# ckkckk


    It's ac simulation, so whatever you use for amplitude, it does not matter. you should get same results

hezudao

回复 3# wkjatzju


    I mean if you want to understand why gain is low, you should at least know how to analyze your circuit. You probably already have a number in mind before you run simulation. To drive 100 ohm, you might need at least more than 1.25mA to get positive gain(in dB). Check your current. Is there any CMOS circuit design course taught in ZJU now?

netshell

回复 6# hezudao


    QQ  125538673 可否加我？