jimito13
Advanced Member level 1
Hello all,
I am designing an active continuous time filter and i have chosen a Tow-Thomas biquad to realize my circuit.My question is the following :
During the design of the opamp and the simulation procedure via cadence spectre,which is the proper load capacitance that i should concider for my opamp circuit?? 1pF or 2pF should be enough? Is there a way to evaluate the proper load capacitance value for my opamp via some kind of simulation of the ideal circuit,that is to measure the capacitance seen at the output of the first opamp for example in the TT biquad?
Apparently i need this info in order to make an initial estimation for the gm value of my differential pair at the input stage to obtain the required transition frequency since 2*pi*ft≈gm1/(Cout+Cload).
So,i need an estimation for the sum Cout+Cload.
Any helpful answer would be appreciated.Thanks in advance.
I am designing an active continuous time filter and i have chosen a Tow-Thomas biquad to realize my circuit.My question is the following :
During the design of the opamp and the simulation procedure via cadence spectre,which is the proper load capacitance that i should concider for my opamp circuit?? 1pF or 2pF should be enough? Is there a way to evaluate the proper load capacitance value for my opamp via some kind of simulation of the ideal circuit,that is to measure the capacitance seen at the output of the first opamp for example in the TT biquad?
Apparently i need this info in order to make an initial estimation for the gm value of my differential pair at the input stage to obtain the required transition frequency since 2*pi*ft≈gm1/(Cout+Cload).
So,i need an estimation for the sum Cout+Cload.
Any helpful answer would be appreciated.Thanks in advance.