Microelectronics

Signals and Amplifiers

Introduction Microelectronics: IC electronics Basic Concepts Signals 12/5/2018 Introduction Microelectronics: IC electronics Basic Concepts Signals Amplification

Signals

Signals Signal → {Transducer} → Electrical Signal → {Processing (Electronic)} → Information. Thevenin Norton

Example 1.1

Signals Time Varying Signal

Frequency Spectrum of Signals

Periodic Signals f = 1/T Hz ω = 2πf rad/s

Frequency Spectrum of Signals Linear System: f(αx)= αf(x) f(x+y)=f(x)+f(y) sin(ωt) → { Linear System } → α sin(ωt+θ) Fourier series or Fourier transform. 𝑓= 1 𝑇 𝜔=2𝜋𝑓= 2𝜋 𝑇

Frequency Spectrum of Signals A symmetrical square-wave signal of amplitude V

Frequency Spectrum of Signals Frequency Spectrum of the Periodic Square Wave

Frequency Spectrum of Signals The Frequency Spectrum of a Non-Periodic Waveform

Analog and Digital Signals

Analog and Digital Signals Analog Signal →{Sampling}→ Discrete Time Signal.

Analog and Digital Signals Discrete Time Signal →{Quantization}→Digital Signal. Digital Signal →{Electronics}→ Binary (e.g. 0 V & + 5V)

A/D (ADC) & D/A (DAC) Many processing systems contain both analog and digital circuits

Amplifiers

The Simplest Processor Linearity: vo(t) = A vi(t) Amplifiers The Simplest Processor Signal Amplification Linearity: vo(t) = A vi(t) A: Const Preamplifier (V) & Power amplifier (I)

Amplifier Circuit Symbols

The Gain

The Gain Amplifier Gain Gain in Decibels Voltage Gain (Av) 20 log | Av | Current Gain (Ai) 20 log |Ai| Power Gain(Ap) Av Ai 10 log |Ap|

Pdc + PI = PL + Pdissipated The Amplifier Power Supplies → (PO - PI) Pdc = V1 I1 + V2 I2 Pdc + PI = PL + Pdissipated ή

Example 1.2 𝑉 𝑆 =±10𝑉 𝑅 𝐿 =1𝑘Ω 𝑣 𝑖 =1sin 𝜔𝑡 𝑉 𝑣 𝑜 =9sin 𝜔𝑡 𝑉 𝐼 𝑆+ = 𝐼 𝑆− =9.5 𝑚𝐴 𝑖 𝑖 =0.1sin 𝜔𝑡 𝑚𝐴 𝐴 𝑣 = 9 =20𝑙𝑜𝑔9 𝐼 𝑜 = 9 𝑚𝐴 𝐴 𝑖 = 90 =20𝑙𝑜𝑔90 =39.1 dB 9 2 9 2 1 2 0.1 2 𝑃 𝐿 = =40.5 mW 𝑃 𝐼 = =0.05 mW 40.5 0.05 𝐴 𝑃 = =810 mW =29.1 dB 𝑃 𝑑𝑐 = 10×9.5+10×9.5=190𝑚𝑊 𝑃 𝐷𝑖𝑠𝑠𝑖𝑝 = 190+0.05−40.5=149.6𝑚𝑊 𝜂=21.3%

Saturation | L– | = | L+ | = | VSS | - (1 V or 2 V)

Nonlinear Transfer Characteristics and Biasing Non-Linearity Q = Quiescent Point = DC Biasing Point = Operating Point

Symbol convention

Circuit Models for Amplifiers

Voltage Amplifiers

Cascaded Amplifiers Example 1.3 Compute: AV, AI, & AP.

Other Amplifier Types

Voltage Amplifier

Current Amplifier

Transconductance Amplifier

Transresistance Amplifier

Other Amplifier Types

Relationships between the Four Amplifier Models

Determining Ri and Ro

Other Amplifier Types

Other Amplifier Types

Other Amplifier Types

Other Amplifier Types

Other Amplifier Types

Signal flows form the input to the output, with no feedback Unilateral Models Signal flows form the input to the output, with no feedback

Example 1.4

Example 1.4

Example 1.4

Example 1.4 Figure 1.19 (a) Small-signal circuit model for a bipolar junction transistor (BJT). (b) The BJT connected as an amplifier with the emitter as a common terminal between input and output (called a common-emitter amplifier). (c) An alternative small-signal circuit model for the BJT.

Frequency Response of Amplifiers

Measuring The Amplifier Frequency Response T(ω) ≡ Amplifier Transfer Function

Amplifier Bandwidth

Evaluating the Frequency Response of Amplifiers S = ( σ + j ω ) ≡ Laplace Operator = ( j ω ) at Steady State

Single Time Constant Networks

Single Time Constant Networks ? LP:

Single Time Constant Networks ? HP:

Bode Plot Magnitude Response Phase Response

Bode Plot: Magnitude Response Corner Frequency

Bode Plot: Phase Response

Magnitude Response Plot for STC LPF

Magnitude Response Plot for STC LPF

Magnitude Response Plot for STC LPF

Magnitude Response Plot for STC LPF

Magnitude Response Plot for STC LPF

3 dB, Cut off , Critical, Corner Frequency Magnitude Response Plot for STC LPF 3 dB, Cut off , Critical, Corner Frequency

3 dB, Cut off , Critical, Corner Frequency Magnitude Response Plot for STC LPF 3 dB, Cut off , Critical, Corner Frequency

Phase Response Plot for STC LPF

Phase Response Plot for STC LPF 12/5/2018 Phase Response Plot for STC LPF ∞

Bode Plot for STC HPF

Bode Plot for STC HPF

Example 1.5 Calculate AV(ω=0), ω0(3-dB), & ω(AV = 0-dB)

Example 1.5

Example 1.5

Example 1.5

Example 1.5

Example 1.5

Classification of Amplifiers Based on Frequency Response

Capacitive Coupling vs. Direct Coupling (dc) Amplifiers