In the circuit of Fig. 12.123, the three stages provide a high gain, approximating an op amp. Assume (W/L)1-6 = 10 μm/ 0.18 μm.
(a) Explain why the circuit is potentially unstable.
(b) Determine the step response and explain the circuit's behavior.
(c) Place a capacitor between nodes X and Y and adjust its value to obtain a well-behaved step response. (d) Determine the gain error of the circuit with respect to the nominal value of 10.
