Negative Feedback in Analog IC Design

These flashcards cover key concepts related to negative feedback in the context of Analog Integrated Circuit Design, summarizing important definitions and properties.

Negative Feedback

A mechanism in control systems where the output is fed back to reduce or counteract changes in the input.

Loop Gain (LG)

Defined as the gain of the feedback loop; calculated as the product of the feedback factor and the open-loop gain.

Error Signal (Verr)

The difference between the input voltage and the feedback voltage in a feedback system.

Closed-Loop Gain (Acl)

The gain of the system when feedback is applied, given by Acl = AOL / (1 + βAOL).

Gain Desensitization

The property of a feedback system that allows the closed-loop gain to be relatively independent of variations in open-loop gain.

Bandwidth Extension

The effect of negative feedback that increases the operational bandwidth of a system, allowing it to function effectively over a wider frequency range.

Stability

In control theory, the ability of a system to maintain performance without oscillations or divergence in output.

Bode Plot

A graphical representation of a system's frequency response, showing the magnitude and phase of the output as a function of frequency.

Phase Margin (PM)

A measure of system stability, defined as the amount of phase shift at the gain crossover frequency.

Gain Margin (GM)

A measure of the stability of a control system, representing how much gain can increase before the system becomes unstable.

Op-Amp (Operational Amplifier)

A high-gain differential amplifier used extensively in analog circuits for various operations including amplification and signal processing.

MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)

A type of transistor used for amplifying or switching electronic signals in various devices.

Cascades

A series of stages in which each stage's output is connected to the input of the next stage, often used in amplifying circuits.

Differential Amplifier

An amplifier that amplifies the difference between two input signals.

Root Locus

A graphical method used in control theory to plot the roots of a transfer function as system parameters vary.

Classic Feedback Topologies

Standard configurations such as Common Source (CS), Common Gate (CG), and Common Drain (CD) used in amplifiers.

Loop Transmission

Another term for loop gain; describes how feedback affects the gain in a control system.

Transistor Saturation

Condition where a transistor is fully 'on' and allows maximum current to flow from collector to emitter.

Gain Crossover Frequency (GX)

The frequency at which the gain of the system's open loop transfer function is equal to one (0 dB).