Lecture Slide 5

Small-signal amplifier

Small-signal amplifier

An amplifier that operates on small variations in input signals.

Large-signal amplifier

An amplifier that operates on large variations in input signals.

Power amplifier

A type of large-signal amplifier that is designed to deliver high power output.

Mixer

A device used to combine two or more input signals to produce an output signal.

Small-signal S-parameters

Parameters used to describe the behavior of a small-signal amplifier.

Nonlinear regions

Operating regions of active devices where their behavior is not linear.

Discrete design

Design using individual components, such as transistors or FETs.

Integrated circuit (IC) design

Design using integrated circuits, where multiple components are integrated onto a single chip.

Large-signal model

A model used to describe the behavior of active components in large-signal circuits.

Eber-Molls model

A large-signal model for bipolar junction transistors (BJTs).

Gummel-Poon model

A large-signal model for BJTs.

Vertical Bipolar Intercompany (VBIC) model

A large-signal model for BJTs.

Berkeley Short-channel IGFET Model (BSIM)

A large-signal model for field effect transistors (FETs).

SPICE-based circuit simulator

A software tool used to simulate the behavior of electronic circuits.

Netlist

A list of components and connections in a circuit.

SPICE Gummel-Poon (SGP) model

A SPICE-based model for BJTs.

BSIM

Berkeley Short-channel IGFET Model, a SPICE-based model for FETs.

Threshold model

A model that describes the behavior of a field-effect transistor based on its threshold voltage.

CMOS technology

Complementary Metal-Oxide-Semiconductor technology, a widely used technology for integrated circuits.

MOSFET

Metal-Oxide-Semiconductor Field-Effect Transistor, a type of FET.

BSIM1, BSIM2, BSIM3, BSIM4, BSIMSOI

Different versions of the BSIM model with increasing complexities and accuracy.

Pennsylvania or Philips Surface Potential (PSP) MOSFET model

An alternative model for MOSFETs developed by Pennsylvania State University and Philips Semiconductor.

Power amplifier

An amplifier designed to deliver high power output.

Class A amplifier

A type of power amplifier that operates in the linear region for the entire input signal cycle.

Class B amplifier

A type of power amplifier that operates in the linear region for only half of the input signal cycle.

Class AB amplifier

A type of power amplifier that combines the characteristics of Class A and Class B amplifiers.

Class C amplifier

A type of power amplifier that operates in the nonlinear region for most of the input signal cycle.

Class D amplifier

A type of power amplifier that uses pulse width modulation to achieve high efficiency.

Class E amplifier

A type of power amplifier that uses resonant circuits to achieve high efficiency.

Class F amplifier

A type of power amplifier that uses harmonic tuning to achieve high efficiency.

Maximum output power

The maximum power that a power amplifier can deliver to the load.

Efficiency

The ratio of output power to input power, usually expressed as a percentage.

Harmonic distortion

The presence of unwanted harmonics in the output signal of an amplifier.

Large-signal power gain

The ratio of output power to input power in a large-signal amplifier, usually expressed in decibels (dB).

Operating voltage

The voltage at which a power amplifier operates.

Bandwidth

The range of frequencies over which a power amplifier can operate effectively.

Isolation

The degree of separation between the input and output of a power amplifier.

CE configuration

Common Emitter configuration, a common configuration for power amplifiers.

CC configuration

Common Collector configuration, another common configuration for power amplifiers.

Class-B Power Amplifier

A type of power amplifier that operates with high efficiency and is suitable for wideband systems. It requires a higher operating voltage and the active device is only active half the time or 180°.

Class AB Operation

By including a small series resistor, a Class-B power amplifier can be turned into Class AB operation, where the active device is active slightly more than half the time or slightly more than 360°.

Push-Pull Configuration

A configuration of a Class-B power amplifier where two active devices are used in tandem to achieve high efficiency and high linearity. The active devices are active half the time or 180°.

Class-C Power Amplifier

A type of power amplifier that operates with high efficiency but poor linearity. It is suitable for narrow-band systems and low voltage systems. The active device is active less than half the time or less than 180°.

Class F Amplifier

A variant of Class B amplifier that achieves even higher efficiency by reactively tuning the harmonics and minimizing power dissipation.

Class E Amplifier

A switching amplifier similar to Class B or F, but it uses a switching principle that loses the analog relationship between input and output.

Class D Amplifier

A switching amplifier that utilizes two active devices in tandem to achieve high efficiency, similar to a push-pull Class F amplifier.

Class A

An amplifier class where conduction occurs over the full 360° of the cycle.

Class AB

An amplifier class where conduction occurs for slightly more than half the cycle, slightly more than 360°.

Class C

An amplifier class where conduction occurs for less than 180° of the cycle, but this creates distortion.

Class D to T

Amplifier classes that utilize non-linear switching techniques to improve efficiency.

Large-Signal Response

One-Tone Excitation:The response of an amplifier characterized by a power series expansion of the input, considering different harmonic terms.

dB Scale

A logarithmic scale used to express power ratios or gains in decibels.

System Impedance

The impedance of the system in which the amplifier is operating.

Reference Power

The power level used as a reference point for measuring power in decibels. In this case, it is referenced to 1 mW.

Saturation

The state of an active component in which it is driven to its maximum output level.

Pin

Input power to the amplifier.

Fundamental

The fundamental frequency term in the power series expansion of the input.

1st Harmonic

The 1st harmonic term in the power series expansion of the input.

2nd Harmonic

The 2nd harmonic term in the power series expansion of the input.

Amplifier Large-Signal Response

The behavior of an amplifier when it is driven by two sinusoidal signals at different frequencies.

Two-Tone Excitation

The use of two sinusoidal signals at different frequencies to drive an amplifier.

Component of Interest

The specific output components that are of interest when implementing a mixer circuit or amplifier.

Intermodulation Distortion (IMD)

Undesirable components that are caused by the interaction of the two input signals in an amplifier, resulting in distortion in the output signal.

Fundamental Component

The output power at the frequencies of the two input signals.

Mixing Component

The output power at the sum and difference frequencies of the two input signals.

Intermodulation Component

The output power at the frequencies that are the sum and difference of multiples of the two input frequencies.

dB Scale

A logarithmic scale used to represent power levels in decibels.

System Impedance

The impedance of the system in which the amplifier is operating.

Pin

The input power level.

Po_f1, Po_f2

The output power at the frequencies of the two input signals.

Po_2f1-f2, Po_2f2-f1

The output power at the frequencies that are the sum and difference of the two input frequencies.

Intermodulation Distortion Components

The output power at the intermodulation frequencies, which are typically close to the fundamental frequencies and result in distorted output signals.

Dynamic Range

The range of input power levels over which an amplifier can operate without significant distortion.

1 dB Gain Compression Point

The input power level at which the gain of the amplifier decreases by 1 dB.

Third Order Intercept Point (TOI)

The input power level at which the third-order intermodulation products reach the same power level as the desired signal.

Spurious-Free Dynamic Range (DRf)

The range of input power levels over which the power of the third-order intermodulation products is lower than the noise power, resulting in negligible distortions.

Large-Signal Parameters

Parameters that describe the behavior of a power amplifier in the dB scale, including Po/dBm, Pin/dBm, DRf, PIP, Po,mds, and P1dB.

IMD

Intermodulation distortion, which is the generation of unwanted signals due to nonlinearities in the power amplifier.

TOI

Third-order intercept point, which is the output power level at which the third-order intermodulation products are equal in magnitude to the desired signal.

DR

Dynamic range, which is the range of input power levels over which the power amplifier can operate linearly.

DRf

Spurious-free dynamic range, which is the output power range over which the power amplifier is considered linear.

Linearity

The ability of a power amplifier to accurately reproduce the input signal without introducing distortion or nonlinearities.

α1, α2, α3

Coefficients that describe the nonlinear behavior of a power amplifier.

H.O.T.

Higher-order terms, which are additional nonlinear terms that can affect the linearity of a power amplifier.

P1dB

1 dB gain compression point, which is the output power level at which the gain of the power amplifier decreases by 1 dB.

IP

Intercept point, which is the output power level at which the intermodulation products are equal in magnitude to the desired signal.

CW

Continuous sine wave, which is a continuous waveform used in testing power amplifiers.

IMD Level

Intermodulation distortion level, which is the level of unwanted signals generated due to nonlinearities in the power amplifier.

AC Load Line

A graphical representation of the relationship between the collector current and collector-emitter voltage in a power amplifier.

Efficiency

The ratio of output power to input power, which indicates how effectively the power amplifier converts input power to output power.

Breakdown Voltage

The voltage at which a power amplifier enters the breakdown region and can no longer operate linearly.

Saturation Region

The region of operation in a power amplifier where the output voltage is at its maximum and the transistor is fully conducting.

Cutoff Region

The region of operation in a power amplifier where the output voltage is at its minimum and the transistor is not conducting.

Load Resistance

The resistance connected to the output of a power amplifier, which affects the output power level and efficiency of the amplifier.

Class-A Power Amplifier

A type of power amplifier that operates in the linear region of its output characteristics, providing high fidelity amplification but low efficiency.

Load Resistance

The impedance presented to the output of a power amplifier, which affects the maximum output power and efficiency of the amplifier.

Parasitic L and C

Unintended inductance and capacitance that exist in a power amplifier circuit, which can complicate the analysis and affect the performance.

Optimum Load Impedance

The load impedance that maximizes the power output at 1 dB compression point (P1 dB) of a power amplifier.

Smith Chart

A graphical tool used to analyze and design impedance matching networks, including the constant P1 dB contour for power amplifiers.

Class-AB Power Amplifier

A type of power amplifier that combines the high fidelity of Class-A amplifiers with the higher efficiency of Class-B amplifiers.