Semiconductor Devices

Norton's Theorem

• Simplifies a one-port circuit to a current source in parallel with an impedance.

Charge Carrier Movement

• Occurs in semiconductors via drift and diffusion.

Diffusion Current Density

• Proportional to the concentration gradient of the carrier.

Bandgap Energy

• The minimum energy required to dislodge an electron from its covalent bond.

Pnpn Junctions

• They experience breakdown under high reverse bias voltage, leading to high current.
• Breakdown type depends on device structure and doping.
• Breakdown is classified as Zener or Avalanche.

Amplifier Statement

• A voltage-dependent current source can form an amplifier with a load resistor.

Transistor Biasing

• Base-emitter junction must is forward-biased
• base-collector junction must be reverse-biased for proper operation.

Bipolar Transistor Model

• It has an exponential voltage-dependent current source between collector and emitter, plus a diode between base and emitter.

Common-Emitter Stage

• Offers moderate voltage gain, input impedance, and output impedance.

Emitter Follower

• Provides voltage gain less than one, with high input and low output impedance.
• Functions as a voltage buffer.

MOSFET Operation (Triode Region)

• MOSFET operates in the triode, the drain voltage must be more than one threshold below the gate voltage.

Miller Effect

• Capacitance between input and output of an inverting amplifier appears at the input, multiplied by one minus the amplifier gain.

Transconductance

• Measures small-signal performance, defined as the change in output current divided by the change in input voltage.

MOSFET Gate Impedance

• The impedance seen looking into the gate of a MOSFET is theoretically infinite.

Noninverting Amplifier

• Its topology exhibits a gain of one plus a resistor ratio.
• Suffers from a gain error inversely proportional to the op amp's gain.

Logarithmic Function

• Using a bipolar device around an op amp provides a logarithmic function.

Op Amp Imperfections

• Op amps have imperfections such as dc offsets and input bias currents, impacting circuits like integrators.

Cascade Transistors

• Stacking a transistor atop another forms a cascade structure, yielding high output impedance.

Bipolar Differential Pairs

• Display a hyperbolic tangent input/output characteristic.
• The tail current directs to one side with a differential input of about 4Vt.

Signal Frequency

• As frequency increases, capacitances exhibit a lower impedance, reducing gain and causing it to roll off.

Transfer Function

• To obtain the frequency response, the transfer function of the circuit must be derived.

Loop Gain

• Obtained by breaking the loop, injecting a test signal, and calculating the gain.
• Determines gain, frequency response, and I/O impedances.

Hard Saturation

• Occurs when a transistor operates at the upper end of the load line, with a base current one-tenth of the collector current.

Oscillation

• To avoid oscillation, the gain crossover frequency must fall below the phase crossover frequency.

Negative Feedback Loop

• Output stage is embedded in negative feedback loop to suppress nonlinearity in low-distortion applications.

Thermal Runaway

• Push-pull stages at high temperatures may experience thermal runaway.
• Elevated temperatures cause higher currents, increasing dissipation.

Chebyshev Response

• Offers a sharper transition than Butterworth, with ripple in passband and stopbands.
• Contains n complex poles on an ellipse.

Avalanche Effect

• Occurs at large reverse voltages across a pn junction.
• Free electrons accelerate, dislodging valence electrons.

Bode Plot

• A graph illustrating gain or phase performance of a circuit at various frequencies.

Bulk Resistance

• Ohmic resistance of the semiconductor is called bulk resistance.

Schmitt Trigger

• A comparator with hysteresis is called Schmitt trigger.

Crowbar

• Metaphor for SCR action, protecting a load against supply surges.

Derating Factor

• Indicates power reduction per degree above the reference temperature.

Doping

• The process of adding impurity elements to change semiconductor conductivity.

Lissajous Pattern

• Pattern on an oscilloscope with harmonically related signals on horizontal and vertical inputs.

Latch

• Connection of two transistors with positive feedback to simulate a thyristor.

Life Time

• Average time between creation and recombination of a free electron and a hole.

Notch Filter

• Blocks a signal at one frequency (or a narrow band of frequencies).

Oscillation

• Term for the death of amplification

Pinch Off Voltage

• Voltage providing the border between ohmic and constant current regions in a depletion-mode device when gate-to-source voltage is zero.

Prototype

• Basic circuit modified for more advanced circuits

Schottky Diode

• Special purpose diode without a depletion layer.

Surge Current

• Large initial current through a rectifier diode

Thyristor

• A four-layer semiconductor device acting as a latch

Trip Point

• Input voltage that switches the output of a comparator

Varistor

• Device acting like two back-to-back zener diodes

Wafer

• Thin crystal slice used as chassis for integrated components

High Field Emission

• Other term for zener effect is high field emission.

Schottky Diode

• Sometimes called hot-carrier diode

Clipper

• Network removing portions of an input signal without distorting the remaining part.

Tetravalent

• Atom with four valence electrons is called tetravalent

Intrinsic

• Term for highly refined semiconductor material with very low impurities

Thompson

• Discovered electrons in Thompsons experiment in 1897

1. 1eV

• Typical energy gap of silicon semiconductor

Germanium

• Semiconductor material sensitive to temperature change

Recombination

• Occurs when a conduction-band electron loses energy and falls into a hole in the valence band

Boron

• Not a pentavalent atom.

Produced Thermally

• Minority carriers are thermally produced.

Reversed Saturated Current

• Small amount of current in a reverse biased diode

10pA

• Typical reverse saturated current of a silicon diode is 10pA

50-1kV

• Typical range of reverse breakdown voltage of silicon diode

Storage Time

• Time required for minority carriers to return to the majority carrier state in the opposite material

Field Programmable Gate Array

• FPGA stands for Field Programmable Gate Array

01001101

• The 2's complement of 10110010 is 01001101

10100101

• Convert the binary number 11000110 to gray code = 10100101

NAND

• Can be used as universal gate

XOR

• Logic gate that produces a HIGH output only when its two inputs are at opposite levels.

De Morgan's Theorems

• Complement of a sum of variables is equal to the product of the complements of the variables.

F=ABC+AB'C+A'B'C'

• Following expression is in standard SOP form

1010

• In a 4 variable K-map, the binary value for the cell in the lower right corner is 1010

Full Adder

• Digital circuit that adds two bits and an input carry to produce a sum and an output carry.

S=1; R=1

• Invalid state for RS flip flop is when S=1; R=1

Toggle

• In T flip flop, T stands for Toggle

2

• Need 2 flip-flop/s is/are need to produce 2kHz frequency from 8kHz input

J=1; K=1

• A flip-flop is in the toggle condition when J=1; K=1

4

• Need 4 flip-flops are needed to produce 4-bit asynchronous counter?

4

• Need How many flip-flops are needed to produce modulus-12 asynchronous counter?

Modulus

• The number of unique states through which a counter will sequence

Ripple Counters

• Asynchronous counters are known as ripple counters

Number of States

• The modulus of a counter is the actual number of states in its sequence

1000

• Three cascaded modulus-10 counters have an overall modulus of 1000

1100

• The terminal count of a modulus-13 binary counter is 1100

Input Offset current

• The difference between two op-amp input currents is called input offset current.

Integrator

• A circuit whose output voltage is proportional to the area, under the curve of the input voltage.

Differentiator

• A circuit whose output voltage is proportional to the slope of the input voltage.

Chebyshev Response

• A filter response that exhibits an equiripple amplitude response in the pass band.

Butterworth Response

• A filter response that exhibits maximum flatness possible in the pass band.

State Table

• Time sequence of inputs, outputs and flip-flop states can be enumerated in a This consists of four sections labeled the present state, input, output and next state.

Cascading

• To connect combinational Iogic circuits, the term cascading refers to connecting the output of one device to the input of a similar device allows one device to drive the other to expand the operational capability

AND

• It is called the "all or nothing” gate

F = (x+y)(x+y)(y+z)

• Express the Boolean function F= xy + x'z in a product of maxterm form.

Delay Time

• In switching transistors, the time between the state change of input and response in output

Just Less Than 1

• The current gain of a common-base BJT configuration

Superbeta

• The current gain of a Darlington pair

Switched-Mode Power Supply

• It is a dc-dc converter with an unregulated input dc voltage and a regulated output voltage.
• The converter circuitry consists of arrangements of inductor, capacitors, diodes, and transistors.
• The transistors are switched between the ON state (saturation) and the OFF state (cutoff) at rates that typically range from 10 kHz to 40 kHz.

Forward Biased

• Logarithmic amplifiers, together with exponential amplifiers are usd to perform analog multiplication.
• If using an Op-Amp and a diode, the diode should be forward biased in the feedback path, replacing R₁ of an inverting op-amp

Cache Memory

• In computers, its a relatively small, high-speed memory that stores the most recently used instructions or data from the larger but slower main memory

1+BA

• The ratio of the input impedance with series feedback to that without feedback

BA > 1

• To start oscillation, you require both BA > 1 and the phase shift around the feedback network must be 180 degrees

Greater Than -29

• In the IC phase-shift oscillator, the ratio of feedback resistor Rf to R₁ must be Greater Than -29

Both Resistors and Capacitors

• In the Wien bridge oscillator, determining frequency

Battery Charger

• A pulsating dc voltage is suitable for the application of a battery charger

Capacitor Filter

• The average (dc) voltage exist across it is is the purpose an a capacitor in the power supply

Decrease the AC voltage component

• The purpose of an additional RC filter section in a power supply circuit is to decrease the ac voltage components

Transistor

• In a simple series regulator circuit, the component that is is is called the controlling element .

1000 us to 5000 us

• Range of gm for JFETs

0. 25 IDSS

• At an ID that the value of ID is gm equal to 0.5 gmo?

MOSFET

• Between a mosfet and FET which has depletion and enhancement types and FET has the least impedance

Zero

• In an FET what number would to IG be to reduce the resistance?

Ohmic

• Referred to right of pinch-off locus as the region

One-Half

• The drain current will always be one-fourth of IDSS as long as the gate-to-source voltage is the pinch-off value.

three or four

• How many terminals does a MOSFET have?

SiO2

• insulatin Layer of in MOSFET construction accounts for very high input impedance

EMOSFET

• he transfer curve is not defined by Shockley's equation for the

JFET

• FETs has lowest input impedance?

32

• How many orbiting elections does germanium have

1. 6 E-19

• One eV is equal to

MA

• Unit is used to represent level of diode forward current?

depletion

• Which capacitance dominates in the reverse-bias region?

Diffusion

• Which capacitance dominates in the forward-bias region?

An Open Diode

• Result when a high resistance reading in both forward- and reverse-bias directions indicate

150 mW

• What is the maximum power rating for LEDs?

Practical

• diode model is employed most frequently in the analysis of electronic systems.

Linear or Active

• the baseemitter junction forward biased and the basecollector junction reverse biased at

forward, forward

• For BJT to operate in saturation the base_emitter junction must be _Biased and teh base Collector junction must be _ biased

VBC

• Voltage must have a neagtiv elvel value in NPN bias circuit

hr

• referred to reverse tramsfer Voltage ratio

Small or Large signal

• In the sinusoidal ac ac alysis of transistor networks?

Hybrid H

• The hybrid model suffers from being limited to a particular set of operating conditions if it is to be considered accurate.

Siemens

• The unit of the parameter ho of a BJT?

Less Than 1

• Typical value of the current gain of a common-base configuration ?

indicates output and input voltages are 180° out

of phase.

• indicates negative sign in the voltage gain of the commonemitter fixedbias configuration

emitter follower

• The configration which has the mostly frequency is used
• frequency is used for impedance matching

small junction capacitance

• Diode that is used as An envelope detector should have

Gunn diode oscillator.

A Noise Limiter

• device that is used in the design to exploit signal diode can be exploited

Photoemission

• As electrons in the atoms of a semiconductor material fall from higher energy levels to lower levels

A Pwer Supply

• Used to supress translents Which could be
• A Thyrector

PNP Reversed Biased.

• In a PNP which has had a Bipolar Transistr, Under those conditions
• Current flow in the collector current
• Has no signal condition

Beta.

• Anohte nane for hfe that is used in Bipoalr traniistor
• Has a stabel singal

Pierece

• oscillator type:
• A device that uses a auarts crystal to ditermien the freq.

Armstrong Oscillator

• A PL frequency synthesizer

Is fed from the output to the

Through a Trasnformer.

• In an armastrong oscullatorm teh singal is from to thru and

The Gain Must Be High

• The feeback Mustt eb postive
• And coupling From output to to impuyt must be GOOD

Audio Signals

• A twin t osoulator is commonly to generaqte Audio sinlgas
• They proidce Low mass Snall Volumeand requiore no mantiance.

Electrolyic Capacitor

• The Simpest pwer -supply filter consits on 1 OF more large vale capactos, Connetced in paralllel wuth rectifier outpt