Question 13.2: FINDING THE PERFORMANCE OF AN OP-AMP INTEGRATOR An op-amp in...
FINDING THE PERFORMANCE OF AN OP-AMP INTEGRATOR
An op-amp integrator circuit is shown in Figure 13.11(a). The input voltage is shown in Figure 13.11(b). Use PSpice to plot the transient response of the output voltage for a duration of 0 to 4 msec in steps of 50 μsec.
The PSpice schematic shown in Figure 13.12(a) with a schematic op-amp model, V_{POS} = 15 V and V_{NEG} = −15 V. The ABM is shown in Figure 13.12(b).
The listing of the circuit file with the op-amp DC model is as follows:
Example 13.2 Integrator circuit with op-amp DC model
| SOURCE VIN 1 0 PULSE (−1V 1V 1MS 1NS 1NS 1MS 2MS) ; Pulse
waveform CIRCUIT R1 1 2 2.5K RF 2 3 1MEG * Vi− Vi+ Vo+ Vo− model name ANALYSIS .TRAN 10US 4MS UIC ; Use initial condition in transient analysis .END |
The plot of the transient response using the op-amp DC model is shown in Figure 13.13. The output voltage is triangular in response to a square-wave input. Equating the areas under two curves, the expected height h is given by 0.5 × 1 msec or h = (1 V + 1 V) × 1 msec, or h = 4 V, which is verified by SPICE simulation.
