EEHDSGN Real Operational Amplifier Circuits

Introduction

Basic operational amplifier (op amp) circuits are covered to death elsewhere. What is commonly not discussed, however, is that real-world (industrial, rugged) op amp circuits are NOT the basic ones commonly shown everywhere.

Real-World Op Amp Circuit Considerations

Real-world considerations (for an op amp in an industrial / commercial product) include the following:

1. Provisions to prevent op amp from oscillation.
2. Provisions to include filtering on op am input.
3. Provisions to balance op amp input impedances, especially when filtering is employed.
4. Picking an appropriate op amp IC type for the project at hand.
5. And many others.

Requisite Concepts

Input/output impedance

Single vs dual power supply rails

Distortion / Nonlinearity

Gain

Feedback

Basic Op Amp Circuits

It would be useful to start from basic circuits, and immediately observe issues with them:

TODO inverting

TODO its parameters

TODO non-inverting

TODO its parameters

TODO differential

TODO its parameters

Non-ideal op amp behaviors

Saturation

Operation close to rails

Nonlinearities

Bandwidth. Also non-linearity of bandwidth

Instability

Common-mode

Offset

Maximum output current

Op amp features

Rail-to-rail input and/or output

Single-supply operation

Rugged industrial designs requirements and concepts

Future part provision

Invariability over manufacturing changes, part changes, temperature, power supply voltage, etc

Gain selectability

Real-World considerations

Missing component / solder joint issues / component cracking

Contamination

Humidity

Tin whiskers

Part discontinuation (EOL)