I am trying to use switched type CMFB of my fully differential amplifier instead of the continous time counter part,
as surely you know such kind of CMFB works with clock control signals,
My problem is that, I never had an experience on how to simulate this amplifier with this type of CMFB. Suppose I want to find the ac charastericiticss from ac simulation, but clocks will be ignored in this simulation.
This problem is not only related to the amplifier, for any circuit working with clock or digital part and I want to perform analog simulation, I have no idea about it
Why don't you try doing ac or stb from transient? Pick a point when you have only the averaging caps connected to the amplifier output, perhaps phase2 of your clocks and when the transient simulation reaches that point run stb.
My problem is that, I never had an experience on how to simulate this amplifier with this type of CMFB. Suppose I want to find the ac charastericiticss from ac simulation, but clocks will be ignored in this simulation.
This problem is not only related to the amplifier, for any circuit working with clock or digital part and I want to perform analog simulation, I have no idea about it
I am looking forward for your help
best regards
Switched-capacitor circuits are sampled data systems. They are a kind of "bridge" between analog and digital systems (time discrete but amplitude continuous).
Therefore, there are some methods to simulate the frequency response (as analysis) of such circuits. For this purpose, the S-C parts have to be replaced by suitable analog elements.
Two methods are described in the literature.
Why don't you try doing ac or stb from transient? Pick a point when you have only the averaging caps connected to the amplifier output, perhaps phase2 of your clocks and when the transient simulation reaches that point run stb.
Switched-capacitor circuits are sampled data systems. They are a kind of "bridge" between analog and digital systems (time discrete but amplitude continuous).
Therefore, there are some methods to simulate the frequency response (as analysis) of such circuits. For this purpose, the S-C parts have to be replaced by suitable analog elements.
Two methods are described in the literature.
Open transient simulation menu. Click on Options > Output, scroll down to ACTMES settings. In actimes enter the desired time and in acnames enter stb. Then, in the analysis set up not only transient but also stb analyses.
Linearization is one method as LvW mentioned. However, if you have SpectreRF license you might try to use periodic simulations (pss, pac, pstb or pnoise).
Some info you can find in Spectre doc:
<spectre_installation>/doc/spectreRFexplorerWorkshop/spectreRFexplorerWorkshop.pdf
<spectre_installation>/tools.lnx86/spectre/examples/SpectreRF_workshop
But it is important to know that methods I was refering to preserve the characteristics of sampled data system (periodic response of the clock period with real zeros)
Linearization is one method as LvW mentioned. However, if you have SpectreRF license you might try to use periodic simulations (pss, pac, pstb or pnoise).
Some info you can find in Spectre doc:
<spectre_installation>/doc/spectreRFexplorerWorkshop/spectreRFexplorerWorkshop.pdf
<spectre_installation>/tools.lnx86/spectre/examples/SpectreRF_workshop