Vijay Vinay
Member level 5
Hello all,
I have come up with a new doubt, this time. I need to calculate the parasitic capacitance for the inputs of my circuit design. I am working in Cadence Virtuoso 6.1 currently and I need guidance regarding the calculation of the parastic capacitance using frequency response (Manually). Previously, I used the Parasitics option within the Plugins option in Cadence Virtuoso 6.1 for calculating the parasitic capacitance. However, now I need to cross check these results using the frequency response curve. I have used a simple technique of sweeping a Vdc supply from 100mV to 2V and measured the input current for my circuit (based on the formula C= I/ (dV/dT)). I got some results which aren't the same as the results I got while using the Parasitics option (~4fF difference). I don't know whether what I have done is correct or not. I have uploaded the pictures of my design here. Right now what I need is, I need to use another method of frequency respone for calculating the capacitance, which I don't know. Could anyone help me to work on this.
FYI, I have used a Vdc supply for sweeping the Vin. I have measured Iin , and calculated Capacitance using C= I/(dV/dT)), C= 28.42fF (I have a question, if this capacitance is Ouput capacitance or Input capacitance. Please answer this question, if you know?)
These are the calculated parasitic capacitances for this circuit using the Parasitics Plugin option within Virtuoso 0.6.1
I have come up with a new doubt, this time. I need to calculate the parasitic capacitance for the inputs of my circuit design. I am working in Cadence Virtuoso 6.1 currently and I need guidance regarding the calculation of the parastic capacitance using frequency response (Manually). Previously, I used the Parasitics option within the Plugins option in Cadence Virtuoso 6.1 for calculating the parasitic capacitance. However, now I need to cross check these results using the frequency response curve. I have used a simple technique of sweeping a Vdc supply from 100mV to 2V and measured the input current for my circuit (based on the formula C= I/ (dV/dT)). I got some results which aren't the same as the results I got while using the Parasitics option (~4fF difference). I don't know whether what I have done is correct or not. I have uploaded the pictures of my design here. Right now what I need is, I need to use another method of frequency respone for calculating the capacitance, which I don't know. Could anyone help me to work on this.
FYI, I have used a Vdc supply for sweeping the Vin. I have measured Iin , and calculated Capacitance using C= I/(dV/dT)), C= 28.42fF (I have a question, if this capacitance is Ouput capacitance or Input capacitance. Please answer this question, if you know?)
These are the calculated parasitic capacitances for this circuit using the Parasitics Plugin option within Virtuoso 0.6.1