Avf, Rif, and Rof

Derive the expressions for closed-loop gain Avf, input resistance Rif, and output resistance Rof of the following image.

Nyquist plot and stability

What are the techniques used to make feedback system stable? Explain and draw the frequency response of a 1-pole feedback amplifier. In a 3-pole feedback amplifier the loop gain is given by: t(f)=(Beta*100)/ ( (1+j*(f/10^4)) * (1+j*(f/10^5))^2 ); Determine the stability for Beta=.5 and .05. Sketch the Nyquist plot for both cases.

BiCMOS folded cascode op-amp

Reference the figure please. Describe the operation of the circuit and discuss its advantages and disadvantages. Iref=80uA Lambdan=lambdap=.02V^-1 kp'=kn'=60uA/V^2 (W/L=30 Va=80V

BJT input diff-amp stage/off-set voltage

Define the offset voltage in the op-amp circuits. Show that the expression for the offset-voltage compensation of BJT input diff-amp stage shown in figure 4 is given by: Vt*ln(ic1/Is3)+ic1R'1=Vt*ln(ic2/Is4)+ic2Rs' Determine the value of x in the potentiometer to compensate for a mismatch between active load transistors Q3 and Q4. Assume Iq=200uA, Is3=10^-14A, Is4=1.1x10^-14A, R1-R2=2K, Rx=100K

non-inverting BiCMOS (CA3140) op-amp circuit

Consider a non-inverting BiCMOS (CA3140) op-amp shown in image 3b. If the input signal is: vi(t)=3*sinwt V Calculate the full-power bandwidth (FPBW) and small-signal bandwidth (f3db) (note :ft=6 Mhz, A0=75k) Sketch the output wave forms for the two inputs shown in image 3b2.