swicap
Member level 5
In this figure, Integrator is in integrate phase. Cs is sampling cap.
Cin is parasitic cap in the input of op, Cf is feedback cap,and Cload
is load cap at the output of integrator.
Ceq in open loop state is given : Ceq_open=Cload+(Cs+Cin)*Cf/(Cs+Cin+Cf)
and Ceq in closd loop state is given: Ceq_close=Ceq_open/feedback_factor
=Cs+Cin+(Cs+Cin+Cf)*Cload/Cf.
Ceq is meaningful for determining OP GBW.
I made some efforts, but didn't derive the formulas above.
Can someone give critical steps or give some useful hint?
Thanks in advance.
Cin is parasitic cap in the input of op, Cf is feedback cap,and Cload
is load cap at the output of integrator.
Ceq in open loop state is given : Ceq_open=Cload+(Cs+Cin)*Cf/(Cs+Cin+Cf)
and Ceq in closd loop state is given: Ceq_close=Ceq_open/feedback_factor
=Cs+Cin+(Cs+Cin+Cf)*Cload/Cf.
Ceq is meaningful for determining OP GBW.
I made some efforts, but didn't derive the formulas above.
Can someone give critical steps or give some useful hint?
Thanks in advance.