Analog Integrated Circuits PDF

Anal o g Ch apter 3 device showing five transistors on a common substrate in a 2-stage The IC Market amplifier arrangement The semiconductor industry is approachin...

Anal o g Ch apter 3 device showing five transistors on a common substrate in a 2-stage The IC Market amplifier arrangement The semiconductor industry is approaching disclosed small cheap of hearing aids $300B / year in sales. 1958 – Integrated Circuit Invented Integrated Circuit September 12, 1958 usually called ICs Jack Kilby at Texas Instruments had built popularly known as silicon chip, a simple oscillator IC with five computer chip, or microchip integrated components (resistors, tiny electronic circuits used to perform capacitors, distributed capacitors and a specific electronic function transistors) a collection of electronic components, In 2000, the importance of the IC was all stuffed into a tiny chip, and recognized when Kilby shared the Noble Prize in connected together to achieve a physics with two others. Kilby was sited by the common goal Nobel Committee “for his part in the invention also known as microchips or of the integrated circuit”. microelectronic circuit a semiconductor wafer that holds thousands and millions of resistors, capacitors, and transistors an assembly of electronic components that is fabricated as a single unit Several hundred integrated circuits (ICs) are made at a time on a thin wafer which is several centimeters wide, and the wafer is subsequently sliced into individual ICs called chips. Advantages of ICs over Discrete Components size: sub-micron vs. millimeter / centimeter speed and power: smaller size of IC components yields higher speed and lower power consumption due to smaller parasitic resistances, capacitances, and inductances o lower power consumption: less heat, cheaper power supplies, reduced system cost integrated circuit manufacturing is versatile Moore’s Law (1965) Designing the layout (changing the masks) is cramming more components onto usually the most time-consuming task in IC integrated circuits design. the number of transistors on an integrated circuit will double every 18 History of IC Technology months Early developments of the Integrated Circuit Gordon E. Moore (IC) go back to 1949. Chairman Emeritus of Intel Corporation Werner Jacobi 1965: observed trends in industry of German engineer who filed a patent for transistors on ICs vs. release dates an IC-like semiconductor amplifying  o noticed number of transistors Scaling cannot go on forever because doubling with release of each new transistors cannot be smaller than atoms. IC generation Analog Integrated Circuits o release dates (separate generations) were all 18-24 months sensors, power management circuits, apart and operational amplifiers work by processing continuous signals Why do we scale MOS transistor? perform functions like amplification, increase device packing density – active filtering, demodulation, and reduces area mixing improve frequency response α 1/L ease the burden on circuit designers improve drive current by having expertly designed analog improve power efficiency circuits available instead of designing a difficult analog circuit from conventional components Digital Integrated Circuits can contain anything from one to millions of logic gates, flip-flops, multiplexers, and other circuits in a few square millimeters small size allows high speed, low power dissipation, and reduced manufacturing cost compared with board-level integration work using binary mathematics to process “one” and “zero” signals Mixed Signal ICs can also combine analog and digital circuits on a single chip to create functions such as A/D converters and D/A converters offer smaller size and lower cost, but must carefully account for signal interference Monolithic ICs built into a single stone or crystal all circuit components and their interconnections are formed into or on the top of a single chip of silicon by far the most common type of ICs used in practice, because of mass production, lower cost, and higher reliability FinFET a type of field-effect transistor (FET) that has a thin vertical fin instead of being completely planar gate is fully “wrapped” around the channel on three sides formed between the source and the drain  the greater surface area created The doped materials are typically impurities of between the gate and channel provides the type p or n and are necessary to form better control of the electric state and devices such as diodes, transistors, conductors reduces leakage compared to planar and IC devices. FETs Heat Treatment (Furnace Annealing) results in much better electrostatic control of the channel and thus better process used in the manufacture of electrical characteristics than planar semiconductor devices which consists of FETs heating multiple wafers of semiconductors to affect their electrical Hybrid ICs properties fabricated by interconnecting a Wafers can be heated to enable dopants (doped number of individual chips material like phosphorus), transfer film to film widely used for high power audio or film to wafer substratum interfaces, densify amplifier applications deposited films, adjust grown film conditions, have better performance than repair implant damage, shift dopants or drive monolithic ICs dopants from one film to another or from a film process is too expensive for mass to wafer substratum. production Merits or Advantages of IC extremely small size – thousand times smaller than discrete circuit o because of fabrication of various circuit elements in a single chip of semi-conductor material very small weight owing to miniaturized circuit very low cost because of simultaneous production of hundreds of similar circuits on a small semiconductor wafer Integrated Circuits Fabrication Techniques o owing to mass production, an IC costs as much as an individual Layering transistor serves to add thin layers to the surface more reliable because of elimination of of the wafer soldered joints and need for fewer inter- connections These layers may be of a different material, low power consumption because of microstructure and composition of the same their smaller size material such as polycrystalline silicon and silicon easy replacement as it is more oxide. economical to replace them than to Patterning (Lithography) repair them increased operating speeds because of the most important step in wafer absence of parasitic capacitance effects fabrication improved functional performance as The deposition, doping, etching, and patterning more complex circuits can be fabricated refer to a series of steps to selectively mask or for achieving better characteristics expose portions of the surface. It sets the no component project above the chip device’s critical dimensions on the wafers. surface is an IC as all the components are formed within the chip Doping Demerits or Disadvantages of IC the process of incorporating specific amounts of electrically active the various components are part of a impurities through openings on the small semi-conductor chip and the surface of the wafers individual component or components  cannot be removed or replaced, Quantum Computer therefore, if any component in an IC fails, the whole IC has to be replaced by the new one limited power rating as it is not possible to manufacture high power (say greater than 10 W) ICs need of connecting inductors and transformers exterior to the semi- conductor chip as it is not possible to fabricate inductors and transformers on the semi-conductor chip surface operations at low voltage as ICs function at fairly low voltage quite delicate in handling as these cannot withstand rough handling or excessive heat need of connecting capacitor exterior to the semi-conductor chip as it is neither convenient nor economical to fabricate capacitances exceeding 30 pF o for higher values of capacitance, discrete components exterior to IC chip are connected low temperature coefficient is difficult to be achieved difficult to fabricate an IC with low noise voltage dependence of resistors and capacitors Intel Corporation’s 49-qubit quantum the diffusion processes and other related computing test chip, code-named “Tangle procedures used in the fabrication Lake,” is unveiled at 2018 CES in Las Vegas. process are not good enough to permit a precise control of the parameter values for the circuit elements Anal o g Ch apter 4 o control of the ratios is at a Amplifier sufficiently acceptable level an electronic circuit or device which increases the amplitude of a signal waveform is same, signal is stronger Operational Amplifier (Op-Amp) historically, was designed to mathematical perform operations such as addition, subtraction, integration and differentiation a multistage amplifier: o differential amplifier stage o high gain CE amplifier stage o class B push pull emitter follower Background of Operational Amplifier originally invented in early 1940s using vacuum tube technology  initial purpose was to execute math operations in analog electronic calculating machines shrunk in size with the invention of the transistor most now made on integrated circuit (IC) huge variety of applications, low cost, and ease of mass production make them extremely popular Ideal Op-Amp Practical Op-Amp ZIN = ∞ ZIN = 2 MΩ ZOUT = 0 ZOUT = 100 Ω AVOL = ∞ AVOL = 105 BW = ∞ BW = GHz Voltage Transfer Characteristic Op-Amp Equivalent Circuit Applications of Operational Amplifier Non-Inverting Amplifier 𝑅 o 𝑉𝑜𝑢𝑡 = 𝑉𝑖𝑛 (1 + 𝑅2) 1 Symbol of Operational Amplifier (Op-Amp) Inverting Amplifier 𝑅 o 𝑉𝑜𝑢𝑡 = − 𝑅 𝑓 𝑉𝑖𝑛 𝑖𝑛 Op-Amp Summing Amplifier 𝑉 𝑉 𝑉 o 𝑉𝑜𝑢𝑡 = −𝑅𝑓 (𝑅1 + 𝑅2 + ⋯ + 𝑅𝑛 ) 1 2 𝑛 Op-Amp Differential Amplifier (𝑅 +𝑅1 )𝑅𝑔 𝑅 o 𝑉𝑜𝑢𝑡 = (𝑅𝑓 +𝑅 𝑉2 − 𝑅𝑓 𝑉1 𝑔 2 )𝑅1 1 o if R1 = R2 and Rf = Rg: 𝑅𝑓 𝑉𝑜𝑢𝑡 = (𝑉2 − 𝑉1 ) 𝑅1 Op-Amp Integrator 1 𝑡 o 𝑉𝑜 = − 𝑅𝐶 ∫0 𝑉𝑑𝑡 Op-Amp Differentiator 𝑑𝑉𝑖𝑛 o 𝑉𝑜 = −𝑅𝐶 𝑑𝑡 Low-Pass Filter (active) 1 o 𝑓𝑐 = 2𝜋𝑅 2𝐶 High-Pass Filter (active) Electrocardiogram (ECG) Applications need to measure difference in voltage from lead 1 and lead 2  60 Hz interference from electrical equipment Simple ECG Circuit o uses differential amplifier to cancel common mode signal and amplify differential mode signal Realistic ECG Circuit o uses two non-inverting amplifiers to first amplify voltage from each lead, followed by differential amplifier o forms an “instrumentation amplifier” Strain Gauge use a Wheatstone bridge to determine the strain of an element by measuring the change in resistance of a strain gauge (No strain) Balanced bridge o R#1 = R#2 (Strain) Unbalanced bridge o R#1 ≠ R#2 Audio Amplifiers speakers and microphone circuits in cell phones, computers, mpg players, boom boxes, etc. Instrumentation Amplifiers biomedical systems including heart monitors and oxygen sensors Power Amplifiers Analog Computers combination of integrators, differentiators, summing amplifiers, and multipliers