Operational Amplifier

Model operational amplifier with two or more poles

• Library:

• Mixed-Signal Blockset / Utilities

• 

Description

Use the Operational Amplifier block to model an operational amplifier with two or more poles. You can create a double pole amplifier from the important circuit parameters or a multiple pole amplifier from transfer function. The operational amplifier model can be used to characterize the operational amplifier performance as part of a larger circuit system.

Ports

Input

InputPlus — Positive input terminal

scalar

Positive input terminal of the operational amplifier.

Data Types: single | double

InputMinus — Negative input terminal

scalar

Negative input terminal of the operational amplifier.

Data Types: single | double

Output

OutputPlus — Positive output terminal

scalar

Positive output terminal of the operational amplifier.

Data Types: single | double

OutputMinus — Negative output terminal

scalar

Negative output terminal of the operational amplifier.

Data Types: single | double

Parameters

Operational Amplifier Circuit — Type of operational amplifier circuit

Double Pole Circuit (default) | Multiple Pole Circuit

Type of the operational amplifier circuit.

• Double Pole Circuit — Use circuit parameters such as open loop gain, unity gain bandwidth, maximum tail current, and slew rate to define a simple double pole circuit.

• Multiple Pole Circuit — Use transfer function poles and zeros to define a multiple pole circuit.

Programmatic Use

Block parameter: CircuitType

Type: character vector

Values: Double Pole Circuit| Multiple Pole Circuit

Default: Double Pole Circuit

Signal Parameters

Supply rail high (V) — Maximum supply voltage

5 (default) | real scalar

Maximum supply voltage provided to the Operational Amplifier block, specified as a real scalar in volts.

Programmatic Use

Block parameter: VoltageSupplyPlus

Type: character vector

Values: real scalar

Default: 5

Supply rail low (V) — Minimum supply voltage

-5 (default) | real scalar

Minimum supply voltage provided to the Operational Amplifier block, specified as a real scalar in volts.

Programmatic Use

Block parameter: VoltageSupplyMinus

Type: character vector

Values: real scalar

Default: -5

Input offset voltage (V) — Offset voltage at operational amplifier input

0 (default) | scalar

Offset voltage at the input of the operational amplifier, specified as a scalar in volts. Input offset voltage is applied to obtain a zero voltage at the output of the operational amplifier.

Programmatic Use

Block parameter: OffsetVoltage

Type: character vector

Values: scalar

Default: 0

Output Resistance (Ohms) — Resistance at operational amplifier output

80 (default) | positive real scalar

Resistance at the output terminals of the operational amplifier, specified as a positive real scalar in ohms.

Programmatic Use

Block parameter: OutputResistance

Type: character vector

Values: positive real scalar

Default: 80

Advanced Parameters

Open loop gain (V/V) — Operational amplifier gain without feedback

855e3 (default) | positive real scalar

The gain of the operational amplifier without any positive or negative feedback, specified as a unitless positive real scalar.

Programmatic Use

Block parameter: Gain

Type: character vector

Values: positive real scalar

Default: 855e3

Unity Gain Bandwidth (Hz) — Frequency at which operational amplifier gain becomes unity

1e8 (default) | positive real scalar

The frequency at which the open loop gain of the operational amplifier becomes unity, specified as a positive real scalar in hertz.

Programmatic Use

Block parameter: FrequencyUnityGain

Type: character vector

Values: positive real scalar

Default: 1e8

Maximum Tail Current (A) — Maximum current passing through tail MOSFET in operational amplifier circuit

100e-6 (default) | scalar

Maximum value of the current passing through the tail MOSFET in the operational amplifier circuit, specified as a scalar in amperes.

Programmatic Use

Block parameter: InputCurrentMax

Type: character vector

Values: scalar

Default: 100e-6

Slew Rate (V/s) — Rate of change of operational amplifier output voltage with time

0.5e6 (default) | positive real scalar

The rate of the change of the output voltage of the operational amplifier with time, specified as a positive real scalar.

Programmatic Use

Block parameter: SlewRate

Type: character vector

Values: positive real scalar

Default: 0.5e6

Transfer function poles — Poles in operational transfer function in Laplace domain

[-2*pi*122; -2*pi*2.1e6; -2*pi*32e6] (default) | column vector

Poles in the transfer function of the operational amplifier in the Laplace domain, specified as a column vector.

Programmatic Use

Block parameter: Poles

Type: character vector

Values: column vector

Default: 80

Transfer function zeroes — Zeros in operational amplifier transfer function in Laplace domain

[2*pi*3.3e6; 2*pi*29e6] (default) | column vector

Zeros in the transfer function of the operational amplifier in the Laplace domain, specified as a column vector.

Programmatic Use

Block parameter: Zeros

Type: character vector

Values: column vector

Default: 80

Sample interval to be used in MATLAB analyses — Sample interval used in MATLAB analyses

1e-8 (default) | scalar

Sample interval used in MATLAB^® analyses, specified as a scalar in seconds.

Programmatic Use

Block parameter: SampleInterval

Type: character vector

Values: scalar

Default: 1e-8

Simulate using — Select simulation mode

Interpreted execution (default) | Code generation

Select the simulation mode. This choice affects the simulation performance.

Simulating the model using the Code generation method requires additional startup time, but the subsequent simulations run faster. Simulating the model using the Interpreted execution method may reduce the startup time, but the subsequent simulations run slower. For more information, see Simulation Modes.

Programmatic Use

Block parameter: SimulateUsing

Type: character vector

Values: Code generation| Interpreted execution

Default: Interpreted execution

Version History

Introduced in R2021b