斩波运放讨论
我做完PSS+PNOISE仿真后，可以在频谱图上看出，奇次斩波频率处有运放输入对管和负载管的1/f噪声，但是这个噪声值相当大，达到了V/sqrt(Hz)了，后面经过低通滤波后也有几十mv/sqrt(Hz),这是不是有什么问题啊！大家有没有相同的 问题?
注意斩波的频率
斩波的频率大于信号的带宽＋corner频率，小于运放带宽的1/10。
楼上的兄弟，运放的带宽是指闭环3dB的带宽还是运放的单位增益带宽呢?多谢！
问一个问题，.noise是要在.ac下使用的，如果用斩波的话，那得用瞬态分析吧，而做瞬态分析的时候好像没有噪声模型啊，小编是怎么做到斩波时候仿真噪声的，希望指导一下
xiexieO(∩_∩)O谢谢
spectra可以做到
can you elaborate your method.
I have tried chopper stabilization tech. on an integrator(for a sigma delta modulator), but I could not see any effect of chopper stabilization.
I think it's impossible to simulate chopper satbilization in nosie analysis or pnoise analysis.
1. For simulation method, acutally some new tools provide transient noise simulation. For other tools, you can try it see the effect by injecting noise to the transientsimulation
2. For chopper stabilization tech. on an integrator(for a sigma delta modulator), 100% sure you can see the effect.I guess you fail to see it mainly due to either you did not put the source or simulation method wrong.
You can very easily experience the effect of chopper by inject a DC in your integrator of your SDM loop. Do FFT after simulation and you will find DC component is much lower with Chopper.
thanks for you comments.
I know that new version of spectre have been added transient analysis.I never ran such analysis. I guess this analysis dose not make sense ifyou have only several runs.
I agree with you that by injecting a dc at input of integrator we can experience chopper stabilization. I meant thatit impossible to see chopper stabilization effect in normal noiseanalysis or pnoise analysis.
看看好不好
看看。
我做的是模拟CMOS 运放，里面加了斩波来降低噪声，请问用Cadence仿噪声，是用pnoise仿真，还是用noise仿，该怎么设置参数?
同问，如何进行斩波仿真?
什么是corner频率?
斩波调制信号的频率应该怎么选择呢，为什么这样选呢?斩波信号的频率越高不是越好么，这样就可以把噪声和失调信号移到更远处。
有资料吗?
您好！
我没有用过pss、pac、pnoise，请问如何仿真斩波运放的增益呢?