Analog Electronics II

Description
The course starts with a presentation of the different amplifier configurations (voltage, current, transconductance, transresistence) and their basic parameters such as gain, and input and output resistances. Then, the course introduces the analog block known as Operational Amplifier (OP-AMP), and describes the desirable characteristics for a voltage-voltage amplifier.

The basic OP-AMP equivalent model is presented along with the most important applications involving signal processing. After that, real constrains and imperfections are added so that a performance comparison can be developed, and the student can decide which model, ideal or real, needs to be employed for analysis or design for the application at hand. Once the OP-AMP has been studied from an equivalent-model point-of-view, its internal blocks are presented (differential input stage, gain stage, output stage, biasing circuits, and frequency compensation schemes). Since covering all the stages requires two courses, Analog Electronics II scopes the differential pair and biasing circuits (current mirrors). A detailed DC and small-signal analyses for the differential pair are provided, and for the current mirrors, the operating principle is presented, and improved architectures are studied as imperfections are added. Lastly, the course studies the performance of the differential pair using an active load, which allows the introduction of the cascode topology.

Usually, when OP-AMPs are used in DC applications, the circuit performance is very close to that studied in theory. However, as the operating frequency of the signals to be processed increases, it can be observed that the performance deviates from that ideal due to the system poles and zeros.
Therefore, the topic on frequency response is included so that the student can gather the needed tools to establish operating ranges and/or design frequency-compensation techniques. For that purpose,
Analog Electronics II presents theorems and tools to facilitate the study of the frequency response of the single amplifier stages, the differential pair and the cascode topology.

Learning Outcomes
At the end of the course the student should be able to understand the operation of the ideal OP-AMP as a basic structure for signal processing, and the effect of the frequency on the performance of the circuits used for this purpose.

• Identify the most important characteristics for an OP-AMP (gain, input and output resistances, saturation, slew rate) and the basic closed-loop configurations.
• Describe the main DC imperfections and include them in the OP-AMP equivalent model.
• Analyze amplifiers using the differential pair with passive load, active load, and cascode topology.
• Identify the OP-AMP main biasing stages.
• Draw magnitude and phase Bode plots for frequency response analysis.
• Identify poles and zeros of the basing amplifier stages and select the appropriate methods for frequency analysis.

Topics

• Course Introduction
• Amplifier Equivalent Circuit Models
• Gain, Input and Output Resistances
• Amplifier Saturation
• Ideal OP AMP
• Inverting Configuration
• Non-inverting Configuration
• Examples of OP-AMP Circuits
• Examples of OP-AMP Circuits
• Large Signal Operation of OP-AMPs
• DC Imperfections
• Introduction to the Differential Pair (BJT)
• Introduction to the Differential Pair (MOSFETs)
• DC Commutation of the Differential Pair
• Large Signal Operation of the Differential Pair
• Small Signal Operations of the Differential Pair
• Differential Pair with Active Load
• Differential Pair with Cascode Configuration
• Non-ideal characteristics of the Differential Pair
• Current Mirrors
• Improved Current Mirrors
• Multistage Amplifier Analysis
• Intro: Frequency Response-Pole-Zero Analysis
• Bode Plots
• Transfer Function of the Amplifier
• Short-circuit Time-Constant Technique
• Augmented Small-signal Model
• High-Frequency Internal Capacitances
• Intuitive Analysis using Time Constants
• Miller?s Theorem: The Miller Effect
• Open-circuit Time-Constant Technique
• Frequency Response of the CS Amplifier
• Frequency Response of the CG Amplifier
• Frequency Response of the Cascode Configuration
• Frequency Response of the CD Amplifier
• Frequency Response of the Differential Amplifier
• Frequency Response of the Differential Amplifier: Common Mode
• Frequency Response Examples

RELATIONSHIP OF COURSE TO STUDENTS OUTCOMES
SOi. Recognition of the need for, and an ability to engage in life-long learning.