User:Jakub.duchon
Low Noise Amplifier Design
[edit | edit source]Tutorial - resources :
May - 2009
LNA for CDMA [1]
Circuit Examples LNAa - different frequency ranges : [2]
BFP740F [3]
June - 2009
Modelithics [4]
Infineon Trasistors for LNA [5]
Infineon BFP620 app Note 60 [6]
LNA Design Queen's Wiki [7]
IEEE CMOS LNA Design [8]
A Scalable High-Frequency Noise Model for Bipolar Transistors with Application to Optimal Transistor Sizing for Low-Noise Amplifier Design [9]
A new calculation approach of transistor noise parameters as afunction of gatewidth and bias current [10]
ADS Tutorial Files - ECE Department University of California Santa Barbara [11]
Tutorial [12]
Neste [13]
Thesis [14]
AT 41533 + biasing [15]
Criteria for the Evaluation of Unconditional Stability of Microwave Linear Two-Ports: A Critical Review and New Proof [16]
Modified determinations of stability criteria for accurate designing the linear two-port amplifiers [17]
A New Criterion for Linear 2-Port Stability Using a Single Geometrically Derived Parameter [18]
White Paper - Overview of the 3GPP Long Term Evolution Physical Layer [19]
Specification
[edit | edit source]The amplifier is usually part of a system which is composed of many blocks. Such a system can be connected in a cascade and when connecting many blocks together behavior of each block must be described. This description is called specification. The specification is set of parameters specifying behavior of particular block. Parameter in specification care for example an operating point, input and output parameters, extreme working conditions, supply. Specification is a language how engineers communicate between each other. Specification sets a course of the product development.
Parameter | min | typ | max | unit | Note |
---|---|---|---|---|---|
Center frequency | Hz | ||||
Bandwidth | Hz | ||||
Gain | dB | ||||
Gain Flatness | dB | ||||
RL input | dB | ||||
RL output | dB | ||||
Noise Figure | dB | ||||
OIP3 | dBm | ||||
Consumption | dBm | ||||
Stability | - | ||||
Size | |||||
Cost | € | ||||
Temperature | °C | ||||
I/O Impedance | Ω |
All parameters should be satisfied within the whole bandwidth.
Transistor Selection
[edit | edit source]Transistor selection affects the whole process of design. This part is very important and special attention has to be paid. Transistor selection can make whole design procedure succeed or fail. The question is from where and how to start finding the best fitting transistor to the specification. Well, it pretty much depends on the specification. Good start can be making a set of priorities and start from the most demanding parameters. It may be a good practice to be a bit pessimistic. Choosing better performing transistors can pay off during the finalization of the design. Based on the specification a priority list can be made.
Selection
[edit | edit source]- Low consumption
- Low Noise Figure
- High Gain
- Price
- ...
Taking this selection list as an example, there is still one parameter missing. Operating frequency has to be considered in parallel with almost all parameters in the list. Operating frequency prompts a technology (BJT, FET, HEMT).
Manufacturers
[edit | edit source]Transistor Models
[edit | edit source]Transistor model can be linear or non-linear.
Linear model
[edit | edit source]Linear model of a transistor is set of s-parameters within a frequency range and with specific bias conditions. Frequency range generally starts from 40 MHz and it ends close to the transient frequency. Bias conditions are typically chosen in a convenient manner. In order to be able analyze the noise properties, the transistor can be also described by noise data. The noise data specify minimum noise figure, optimal input impedance and equivalent noise resistance.
Linear models are used for simulation of stability, gain, noise figure.
Non - Linear model
[edit | edit source]BJT models can be represented by Ebers Mool and Gummel-Poon models. These models are usually described by so called SPICE model representation. SPICE is an acronym for Simulation Program with Integrated Emphasis. One of such a program is ADS (Advance Design Software). ADS is software developed by Agilent Technologies and this tutorial uses it as a tool for simulations.
Formula 1
[edit | edit source]Input reflection coefficient
Output reflection coefficient
Noise Figure of a device characterized by noise parameters
Stability factor K
Load and Source Stability Circles: radius and center
Unilateral Figure of Merit
Formula 2
[edit | edit source]Simultaneous conjugate match
Matched source reflection coefficient
Matched load reflection coefficient
Optimal matching
Reflection coefficient -> Impedance
Formula 3
[edit | edit source]Dynamic Range
Stability Factor
Noise Figure