A balanced fully differential circuit displays only odd-order nonlinearity. Use SPICE to verify this fact for the

Question:

A balanced fully differential circuit displays only odd-order nonlinearity. Use SPICE to verify this fact for the op amp in the example in Section 12.6.1.

(a) Either use SPICE to find the distortion in the output waveform for a low-frequency differential sinusoidal input, or use SPICE to plot the dc transfer characteristic V_od versus V_id and verify that the characteristic is odd.

(b) Repeat (a) with a 1 percent mismatch between W₁ and W₂. Observe that even-order nonlinearity now exists.