8.11.2. Operational Amplifier¶
####################################################################################################
import numpy as np
import matplotlib.pyplot as plt
####################################################################################################
import PySpice.Logging.Logging as Logging
logger = Logging.setup_logging()
####################################################################################################
from PySpice.Plot.BodeDiagram import bode_diagram
from PySpice.Probe.Plot import plot
from PySpice.Spice.Netlist import Circuit
from PySpice.Unit import *
from OperationalAmplifier import BasicOperationalAmplifier
#f# literal_include('OperationalAmplifier.py')
####################################################################################################
circuit = Circuit('Operational Amplifier')
# AC 1 PWL(0US 0V 0.01US 1V)
circuit.SinusoidalVoltageSource('input', 'in', circuit.gnd, amplitude=1@u_V)
circuit.subcircuit(BasicOperationalAmplifier())
circuit.X('op', 'BasicOperationalAmplifier', 'in', circuit.gnd, 'out')
circuit.R('load', 'out', circuit.gnd, 470@u_Ω)
simulator = circuit.simulator(temperature=25, nominal_temperature=25)
analysis = simulator.ac(start_frequency=1@u_Hz, stop_frequency=100@u_MHz, number_of_points=5, variation='dec')
figure, (ax1, ax2) = plt.subplots(2, figsize=(20, 10))
plt.title("Bode Diagram of an Operational Amplifier")
bode_diagram(axes=(ax1, ax2),
frequency=analysis.frequency,
gain=20*np.log10(np.absolute(analysis.out)),
phase=np.angle(analysis.out, deg=False),
marker='.',
color='blue',
linestyle='-',
)
plt.tight_layout()
plt.show()
#f# save_figure('figure', 'operational-amplifier.png')
import numpy as np
import matplotlib.pyplot as plt
import PySpice.Logging.Logging as Logging
logger = Logging.setup_logging()
from PySpice.Plot.BodeDiagram import bode_diagram
from PySpice.Probe.Plot import plot
from PySpice.Spice.Netlist import Circuit
from PySpice.Unit import *
from OperationalAmplifier import BasicOperationalAmplifier
####################################################################################################
from PySpice.Spice.Netlist import SubCircuitFactory
from PySpice.Unit import *
####################################################################################################
class BasicOperationalAmplifier(SubCircuitFactory):
NAME = 'BasicOperationalAmplifier'
NODES = ('non_inverting_input', 'inverting_input', 'output')
##############################################
def __init__(self):
super().__init__()
# Input impedance
self.R('input', 'non_inverting_input', 'inverting_input', 10@u_MΩ)
# dc gain=100k and pole1=100hz
# unity gain = dcgain x pole1 = 10MHZ
self.VCVS('gain', 1, self.gnd, 'non_inverting_input', 'inverting_input', voltage_gain=kilo(100))
self.R('P1', 1, 2, 1@u_kΩ)
self.C('P1', 2, self.gnd, 1.5915@u_uF)
# Output buffer and resistance
self.VCVS('buffer', 3, self.gnd, 2, self.gnd, 1)
self.R('out', 3, 'output', 10@u_Ω)
####################################################################################################
class BasicComparator(SubCircuitFactory):
NAME = 'BasicComparator'
NODES = ('non_inverting_input', 'inverting_input',
'voltage_plus', 'voltage_minus',
'output')
##############################################
def __init__(self,):
super().__init__()
# Fixme: ngspice is buggy with such subcircuit
# Fixme: how to pass voltage_plus, voltage_minus ?
# output_voltage_minus, output_voltage_plus = 0, 15
# to plug the voltage source
self.R(1, 'voltage_plus', 'voltage_minus', 1@u_MΩ)
self.NonLinearVoltageSource(1, 'output', 'voltage_minus',
expression='V(non_inverting_input, inverting_input)',
# table=((-micro(1), output_voltage_minus),
# (micro(1), output_voltage_plus))
table=(('-1uV', '0V'), ('1uV', '15V'))
)
circuit = Circuit('Operational Amplifier')
# AC 1 PWL(0US 0V 0.01US 1V)
circuit.SinusoidalVoltageSource('input', 'in', circuit.gnd, amplitude=1@u_V)
circuit.subcircuit(BasicOperationalAmplifier())
circuit.X('op', 'BasicOperationalAmplifier', 'in', circuit.gnd, 'out')
circuit.R('load', 'out', circuit.gnd, 470@u_Ω)
simulator = circuit.simulator(temperature=25, nominal_temperature=25)
analysis = simulator.ac(start_frequency=1@u_Hz, stop_frequency=100@u_MHz, number_of_points=5, variation='dec')
figure, (ax1, ax2) = plt.subplots(2, figsize=(20, 10))
plt.title("Bode Diagram of an Operational Amplifier")
bode_diagram(axes=(ax1, ax2),
frequency=analysis.frequency,
gain=20*np.log10(np.absolute(analysis.out)),
phase=np.angle(analysis.out, deg=False),
marker='.',
color='blue',
linestyle='-',
)
plt.tight_layout()
plt.show()
![../../_images/operational-amplifier.png](../../_images/operational-amplifier.png)