SlideShare a Scribd company logo
1 of 14
MOSFET I-V Characteristics
Contents
•Types
•Cut off region
•Linear region
•Saturation region
•Comparison
•Conclusion and References
1Prepared By S ARUN M.Tech MOSFET VI Characteristics
Characteristics comes under three
category
• Cut-off region
• Linear region
• Saturation region
Prepared By S ARUN M.Tech MOSFET VI Characteristics
MOSFET I-V Characteristics : Cutoff Region
•When VGS < VT, there is no channel formed between the
Drain and Source and hence IDS=0 A
•This region is called the Cutoff Region
•This region of operation is when the Transistor is OFF
Prepared By S ARUN M.Tech MOSFET VI Characteristics
MOSFET I-V Characteristics : Linear Region
• When VGS> VT, a channel is formed. IDS is
dependant on the VDS voltage
• When VDS= 0v, no current flows
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• If VGS> VT and VDS> 0, then a current will flow from the Drain to
Source (IDS).The MOSFET operates like a voltage controlled
resistor which yields a linear relationship between the applied
voltage (VDS) and the resulting current (IDS)
• For this reason, this mode of operation is called the Linear
Region.This region is also sometimes called the triode region
(we'll use the term "linear")
• VDS can increase up to a point where the current ceases to
increase linearly (saturation)
• We denote the highest voltage that VDS can reach and still yield
a linear increase in current as the saturation voltage or VDSAT
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• when a voltage is applied at VD,its positive charge pushes
the majority charge carriers (holes) that exist at the edge of the
depletion region further from the Drain.
• As the depletion region increases, it becomes more difficult for the
Gate voltage to induce an inversion layer. This results in the
inversion layer depth decreasing near the drain.
• As VD increases further, it eventually causes the inversion layer to
be pinched-off and prevents the current flow to increase any
further.
• This point is defined as the saturation voltage (VDSAT)
• From this, we can define the linear region as:
VGS>VT
0 < VDS < VDSATPrepared By S ARUN M.Tech MOSFET VI Characteristics
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• The Drain to Source current (IDS) is given by the
expression:
• Where:
un = electron surface mobility (units in cm2
/V·s)
Cox = Unit Oxide Capacitance (units in F/cm2
)
W = width of the gate
L = length of the gate
• Remember this expression is only valid when :
VGS>VT
0 < VDS < VDSAT
( )[ ]2
02
2
DSDSTGS
oxn
DS VVVV
L
WCu
I linear
−⋅−⋅⋅⋅
⋅
=
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• what is linear about this equation?
• Most of the parameters are constants during evaluation.
They are sometimes lumped into single parameters
• Notice that W and L are parameters that the designers have
control over. Most of the other parameters are defined by
the fabrication process and are out of the control of the IC
designer.
( )[ ]2
02
2
DSDSTGS
oxn
DS VVVV
L
WCu
I linear
−⋅−⋅⋅⋅
⋅
=
oxn Cuk ⋅=' ( )[ ]2
02
2
'
DSDSTGSDS VVVV
L
Wk
I linear
−⋅−⋅⋅⋅=
L
W
Cuk oxn ⋅⋅= ( )[ ]2
02
2
DSDSTGSDS VVVV
k
I linear
−⋅−⋅⋅=
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• What is linear about this equation?
• The -VDS
2
term alters the function shape in the linear region.
As it becomes large enough to significantly decrease IDSin
this function, the transistor enters saturation and this
expression is no longer valid.
( )[ ]2
02
2
DSDSTGSDS VVVV
k
I linear
−⋅−⋅⋅=
For a fixed VGS,
then
IDS depends on
VDS
VDS
2
has a smaller effect on
IDS at low values of VDS
since it is not multiplied by
anything
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• Since we know what the current will not decrease as VDS
increases past VDSAT, we can usethis expression to define VDSAT
• when VDS>(VGS-VT), then IDS in this expression begins to decrease
• we can then define VDSAT = (VGS-VT)
• So now we have the formal limits on the linear region and the validity of
this expression:
•
Linear Region : VGS>VT
0 < VDS < (VGS-VT)
( )[ ]2
02
2
DSDSTGSDS VVVV
k
I linear
−⋅−⋅⋅=
Prepared By S ARUN M.Tech MOSFET VI Characteristics
MOSFET I-V Characteristics : Saturation Region
• MOSFET is defined as being in saturation when:
Saturation Region : VGS> VT and VDS > (VGS-VT)
• An increase in VDS does not increase IDS because the channel is pinched-off
• However, an increase in VGS DOES increase IDSby increasing the channel
depth and hence the amount of current that can be conducted.
• Measurements on MOSFETS have shown that the dependence of IDS on VGS
tends to remain approximately constant around the peak value reached
for VDS=VDSAT
• A substitution of VDS=(VGS-VT0) yields:
( ) ( ) ( )[ ]
( )2
0
2
000
2
2
2
TGSDS
TGSTGSTGSDS
VV
k
I
VVVVVV
k
I
sat
sat
−⋅=
−−−⋅−⋅⋅=
Prepared By S ARUN M.Tech MOSFET VI Characteristics
1st order expressions for all three
regions of operation for the MOSFET
Now we have
Region Conditions IDS
Cutoff VGS< VT
Linear VGS> VT
VDS < (VGS-VT)
Saturation VGS> VT
VDS > (VGS-VT)
0=cutoffDSI
( )2
0
2
TGSDS VV
k
I sat
−⋅=
( )[ ]2
02
2
DSDSTGSDS VVVV
k
I linear
−⋅−⋅⋅=
Prepared By S ARUN M.Tech MOSFET VI Characteristics
• Conclusion
In this presentation conclude that came to know
regards VI characteristics of MOSFET.
• References
 Sedra and smith, “Microelectronic circuits”,7th
Ed.,
Oxford University Press.
Thomas L.Floyd, “Electronic devices” Conventional
current version, Pearson prentice hall.
Robert L.Boylestad, “Electronic devices and circuit
theory”,

More Related Content

What's hot (20)

Mosfet short channel effects
Mosfet short channel effectsMosfet short channel effects
Mosfet short channel effects
 
Fabrication of diodes, resistors, capacitors, fe ts
Fabrication of diodes, resistors, capacitors, fe tsFabrication of diodes, resistors, capacitors, fe ts
Fabrication of diodes, resistors, capacitors, fe ts
 
Mosfet
MosfetMosfet
Mosfet
 
Ece 334 lecture 15-mosfet-basics
Ece 334 lecture 15-mosfet-basicsEce 334 lecture 15-mosfet-basics
Ece 334 lecture 15-mosfet-basics
 
CMOS
CMOS CMOS
CMOS
 
MOS as Diode, Switch and Active Resistor
MOS as Diode, Switch and Active ResistorMOS as Diode, Switch and Active Resistor
MOS as Diode, Switch and Active Resistor
 
3.bipolar junction transistor (bjt)
3.bipolar junction transistor (bjt)3.bipolar junction transistor (bjt)
3.bipolar junction transistor (bjt)
 
Channel length Modulation
Channel length ModulationChannel length Modulation
Channel length Modulation
 
Lightly Doped Drain
Lightly Doped DrainLightly Doped Drain
Lightly Doped Drain
 
15 mosfet threshold voltage
15 mosfet threshold voltage15 mosfet threshold voltage
15 mosfet threshold voltage
 
WPE
WPEWPE
WPE
 
Presentation on Scaling
Presentation on ScalingPresentation on Scaling
Presentation on Scaling
 
Short channel effects
Short channel effectsShort channel effects
Short channel effects
 
SHORT CHANNEL EFFECTS IN MOSFETS- VLSI DESIGN
SHORT CHANNEL EFFECTS IN MOSFETS- VLSI DESIGNSHORT CHANNEL EFFECTS IN MOSFETS- VLSI DESIGN
SHORT CHANNEL EFFECTS IN MOSFETS- VLSI DESIGN
 
FET Biasing
FET BiasingFET Biasing
FET Biasing
 
Field Effect Transistor ppt
Field Effect Transistor pptField Effect Transistor ppt
Field Effect Transistor ppt
 
Zener diodes
Zener diodesZener diodes
Zener diodes
 
Mosfet
MosfetMosfet
Mosfet
 
MOSFETs
MOSFETsMOSFETs
MOSFETs
 
Field Effect Transistor (FET)
Field Effect Transistor (FET)Field Effect Transistor (FET)
Field Effect Transistor (FET)
 

Similar to Mosfet

FET lecture_Electronics by Arif Sir
FET lecture_Electronics by Arif SirFET lecture_Electronics by Arif Sir
FET lecture_Electronics by Arif SirMuntasir Mahdi
 
The electronics industry has achie ved a
The electronics industry has achie ved aThe electronics industry has achie ved a
The electronics industry has achie ved assuser6feece1
 
Electronics 1 : Chapter # 08 : Field effect transistor
Electronics 1 : Chapter # 08 : Field effect transistorElectronics 1 : Chapter # 08 : Field effect transistor
Electronics 1 : Chapter # 08 : Field effect transistorSk_Group
 
Inverters_VLSI_Design powerpoint presentation
Inverters_VLSI_Design powerpoint presentationInverters_VLSI_Design powerpoint presentation
Inverters_VLSI_Design powerpoint presentationAhujaAhuja3
 
Mosfet device structures and characteristics
Mosfet device structures and characteristicsMosfet device structures and characteristics
Mosfet device structures and characteristicsVj S
 
(Latest) topic 5 field_effect_transistors
(Latest) topic 5 field_effect_transistors(Latest) topic 5 field_effect_transistors
(Latest) topic 5 field_effect_transistorsGabriel O'Brien
 
mosfet ppt.pptx
mosfet ppt.pptxmosfet ppt.pptx
mosfet ppt.pptx8885684828
 
Rec101 unit ii (part 3) field effect transistor
Rec101 unit ii (part 3) field effect transistorRec101 unit ii (part 3) field effect transistor
Rec101 unit ii (part 3) field effect transistorDr Naim R Kidwai
 
Chap16-1-NMOS-Inverter.pdf
Chap16-1-NMOS-Inverter.pdfChap16-1-NMOS-Inverter.pdf
Chap16-1-NMOS-Inverter.pdfahmedsalim244821
 
Mosfet Operation and Charecteristics.
Mosfet Operation and Charecteristics.Mosfet Operation and Charecteristics.
Mosfet Operation and Charecteristics.Rafsan Rafin Khan
 

Similar to Mosfet (20)

FET lecture_Electronics by Arif Sir
FET lecture_Electronics by Arif SirFET lecture_Electronics by Arif Sir
FET lecture_Electronics by Arif Sir
 
The electronics industry has achie ved a
The electronics industry has achie ved aThe electronics industry has achie ved a
The electronics industry has achie ved a
 
ch3-DMOSFET.pptx
ch3-DMOSFET.pptxch3-DMOSFET.pptx
ch3-DMOSFET.pptx
 
VLSI_MOS.pptx
VLSI_MOS.pptxVLSI_MOS.pptx
VLSI_MOS.pptx
 
E- MOSFET
E- MOSFETE- MOSFET
E- MOSFET
 
Electronics 1 : Chapter # 08 : Field effect transistor
Electronics 1 : Chapter # 08 : Field effect transistorElectronics 1 : Chapter # 08 : Field effect transistor
Electronics 1 : Chapter # 08 : Field effect transistor
 
Inverters_VLSI_Design powerpoint presentation
Inverters_VLSI_Design powerpoint presentationInverters_VLSI_Design powerpoint presentation
Inverters_VLSI_Design powerpoint presentation
 
MOSFET.pptx
MOSFET.pptxMOSFET.pptx
MOSFET.pptx
 
Mosfet device structures and characteristics
Mosfet device structures and characteristicsMosfet device structures and characteristics
Mosfet device structures and characteristics
 
VLSI- Unit I
VLSI- Unit IVLSI- Unit I
VLSI- Unit I
 
(Latest) topic 5 field_effect_transistors
(Latest) topic 5 field_effect_transistors(Latest) topic 5 field_effect_transistors
(Latest) topic 5 field_effect_transistors
 
mosfet ppt.pptx
mosfet ppt.pptxmosfet ppt.pptx
mosfet ppt.pptx
 
Rec101 unit ii (part 3) field effect transistor
Rec101 unit ii (part 3) field effect transistorRec101 unit ii (part 3) field effect transistor
Rec101 unit ii (part 3) field effect transistor
 
MODULE 2 FET.pptx
MODULE 2 FET.pptxMODULE 2 FET.pptx
MODULE 2 FET.pptx
 
Chap16-1-NMOS-Inverter.pdf
Chap16-1-NMOS-Inverter.pdfChap16-1-NMOS-Inverter.pdf
Chap16-1-NMOS-Inverter.pdf
 
MEC.pptx
MEC.pptxMEC.pptx
MEC.pptx
 
FET (Field Effect Transistors)
FET (Field Effect Transistors)FET (Field Effect Transistors)
FET (Field Effect Transistors)
 
mos character..ppt
mos character..pptmos character..ppt
mos character..ppt
 
Mosfet Operation and Charecteristics.
Mosfet Operation and Charecteristics.Mosfet Operation and Charecteristics.
Mosfet Operation and Charecteristics.
 
MOSFET.pptx
MOSFET.pptxMOSFET.pptx
MOSFET.pptx
 

More from sarunkutti

More from sarunkutti (20)

Multi stage amp
Multi stage ampMulti stage amp
Multi stage amp
 
Differential amplifier
Differential amplifierDifferential amplifier
Differential amplifier
 
Oscillator
OscillatorOscillator
Oscillator
 
Fb amplifier (2)
Fb amplifier (2)Fb amplifier (2)
Fb amplifier (2)
 
Load line analysis
Load line analysisLoad line analysis
Load line analysis
 
Biasing
BiasingBiasing
Biasing
 
Bjt
BjtBjt
Bjt
 
Lcd
LcdLcd
Lcd
 
Clipper and clamper
Clipper and clamperClipper and clamper
Clipper and clamper
 
Surge diverter
Surge diverterSurge diverter
Surge diverter
 
Insulator
InsulatorInsulator
Insulator
 
Insulation coordination
Insulation coordinationInsulation coordination
Insulation coordination
 
Circuit breaker
Circuit breakerCircuit breaker
Circuit breaker
 
Impulse voltage
Impulse voltageImpulse voltage
Impulse voltage
 
Impulse current
Impulse currentImpulse current
Impulse current
 
Dc voltage
Dc voltageDc voltage
Dc voltage
 
Ac voltage
Ac voltageAc voltage
Ac voltage
 
Ac voltage
Ac voltageAc voltage
Ac voltage
 
Triggatron gap
Triggatron gapTriggatron gap
Triggatron gap
 
Ac impulse voltage
Ac impulse voltageAc impulse voltage
Ac impulse voltage
 

Recently uploaded

『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书
『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书
『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书rnrncn29
 
11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdf11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdfHafizMudaserAhmad
 
List of Accredited Concrete Batching Plant.pdf
List of Accredited Concrete Batching Plant.pdfList of Accredited Concrete Batching Plant.pdf
List of Accredited Concrete Batching Plant.pdfisabel213075
 
Cost estimation approach: FP to COCOMO scenario based question
Cost estimation approach: FP to COCOMO scenario based questionCost estimation approach: FP to COCOMO scenario based question
Cost estimation approach: FP to COCOMO scenario based questionSneha Padhiar
 
Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...
Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...
Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...Erbil Polytechnic University
 
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.elesangwon
 
Main Memory Management in Operating System
Main Memory Management in Operating SystemMain Memory Management in Operating System
Main Memory Management in Operating SystemRashmi Bhat
 
Katarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School CourseKatarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School Coursebim.edu.pl
 
Theory of Machine Notes / Lecture Material .pdf
Theory of Machine Notes / Lecture Material .pdfTheory of Machine Notes / Lecture Material .pdf
Theory of Machine Notes / Lecture Material .pdfShreyas Pandit
 
Module-1-(Building Acoustics) Noise Control (Unit-3). pdf
Module-1-(Building Acoustics) Noise Control (Unit-3). pdfModule-1-(Building Acoustics) Noise Control (Unit-3). pdf
Module-1-(Building Acoustics) Noise Control (Unit-3). pdfManish Kumar
 
Computer Graphics Introduction, Open GL, Line and Circle drawing algorithm
Computer Graphics Introduction, Open GL, Line and Circle drawing algorithmComputer Graphics Introduction, Open GL, Line and Circle drawing algorithm
Computer Graphics Introduction, Open GL, Line and Circle drawing algorithmDeepika Walanjkar
 
Triangulation survey (Basic Mine Surveying)_MI10412MI.pptx
Triangulation survey (Basic Mine Surveying)_MI10412MI.pptxTriangulation survey (Basic Mine Surveying)_MI10412MI.pptx
Triangulation survey (Basic Mine Surveying)_MI10412MI.pptxRomil Mishra
 
Robotics Group 10 (Control Schemes) cse.pdf
Robotics Group 10  (Control Schemes) cse.pdfRobotics Group 10  (Control Schemes) cse.pdf
Robotics Group 10 (Control Schemes) cse.pdfsahilsajad201
 
Prach: A Feature-Rich Platform Empowering the Autism Community
Prach: A Feature-Rich Platform Empowering the Autism CommunityPrach: A Feature-Rich Platform Empowering the Autism Community
Prach: A Feature-Rich Platform Empowering the Autism Communityprachaibot
 
Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...
Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...
Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...Sumanth A
 
Comprehensive energy systems.pdf Comprehensive energy systems.pdf
Comprehensive energy systems.pdf Comprehensive energy systems.pdfComprehensive energy systems.pdf Comprehensive energy systems.pdf
Comprehensive energy systems.pdf Comprehensive energy systems.pdfalene1
 
Forming section troubleshooting checklist for improving wire life (1).ppt
Forming section troubleshooting checklist for improving wire life (1).pptForming section troubleshooting checklist for improving wire life (1).ppt
Forming section troubleshooting checklist for improving wire life (1).pptNoman khan
 
ROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.ppt
ROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.pptROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.ppt
ROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.pptJohnWilliam111370
 
Turn leadership mistakes into a better future.pptx
Turn leadership mistakes into a better future.pptxTurn leadership mistakes into a better future.pptx
Turn leadership mistakes into a better future.pptxStephen Sitton
 

Recently uploaded (20)

『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书
『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书
『澳洲文凭』买麦考瑞大学毕业证书成绩单办理澳洲Macquarie文凭学位证书
 
11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdf11. Properties of Liquid Fuels in Energy Engineering.pdf
11. Properties of Liquid Fuels in Energy Engineering.pdf
 
List of Accredited Concrete Batching Plant.pdf
List of Accredited Concrete Batching Plant.pdfList of Accredited Concrete Batching Plant.pdf
List of Accredited Concrete Batching Plant.pdf
 
Cost estimation approach: FP to COCOMO scenario based question
Cost estimation approach: FP to COCOMO scenario based questionCost estimation approach: FP to COCOMO scenario based question
Cost estimation approach: FP to COCOMO scenario based question
 
Designing pile caps according to ACI 318-19.pptx
Designing pile caps according to ACI 318-19.pptxDesigning pile caps according to ACI 318-19.pptx
Designing pile caps according to ACI 318-19.pptx
 
Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...
Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...
Comparative study of High-rise Building Using ETABS,SAP200 and SAFE., SAFE an...
 
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
2022 AWS DNA Hackathon 장애 대응 솔루션 jarvis.
 
Main Memory Management in Operating System
Main Memory Management in Operating SystemMain Memory Management in Operating System
Main Memory Management in Operating System
 
Katarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School CourseKatarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School Course
 
Theory of Machine Notes / Lecture Material .pdf
Theory of Machine Notes / Lecture Material .pdfTheory of Machine Notes / Lecture Material .pdf
Theory of Machine Notes / Lecture Material .pdf
 
Module-1-(Building Acoustics) Noise Control (Unit-3). pdf
Module-1-(Building Acoustics) Noise Control (Unit-3). pdfModule-1-(Building Acoustics) Noise Control (Unit-3). pdf
Module-1-(Building Acoustics) Noise Control (Unit-3). pdf
 
Computer Graphics Introduction, Open GL, Line and Circle drawing algorithm
Computer Graphics Introduction, Open GL, Line and Circle drawing algorithmComputer Graphics Introduction, Open GL, Line and Circle drawing algorithm
Computer Graphics Introduction, Open GL, Line and Circle drawing algorithm
 
Triangulation survey (Basic Mine Surveying)_MI10412MI.pptx
Triangulation survey (Basic Mine Surveying)_MI10412MI.pptxTriangulation survey (Basic Mine Surveying)_MI10412MI.pptx
Triangulation survey (Basic Mine Surveying)_MI10412MI.pptx
 
Robotics Group 10 (Control Schemes) cse.pdf
Robotics Group 10  (Control Schemes) cse.pdfRobotics Group 10  (Control Schemes) cse.pdf
Robotics Group 10 (Control Schemes) cse.pdf
 
Prach: A Feature-Rich Platform Empowering the Autism Community
Prach: A Feature-Rich Platform Empowering the Autism CommunityPrach: A Feature-Rich Platform Empowering the Autism Community
Prach: A Feature-Rich Platform Empowering the Autism Community
 
Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...
Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...
Robotics-Asimov's Laws, Mechanical Subsystems, Robot Kinematics, Robot Dynami...
 
Comprehensive energy systems.pdf Comprehensive energy systems.pdf
Comprehensive energy systems.pdf Comprehensive energy systems.pdfComprehensive energy systems.pdf Comprehensive energy systems.pdf
Comprehensive energy systems.pdf Comprehensive energy systems.pdf
 
Forming section troubleshooting checklist for improving wire life (1).ppt
Forming section troubleshooting checklist for improving wire life (1).pptForming section troubleshooting checklist for improving wire life (1).ppt
Forming section troubleshooting checklist for improving wire life (1).ppt
 
ROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.ppt
ROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.pptROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.ppt
ROBOETHICS-CCS345 ETHICS AND ARTIFICIAL INTELLIGENCE.ppt
 
Turn leadership mistakes into a better future.pptx
Turn leadership mistakes into a better future.pptxTurn leadership mistakes into a better future.pptx
Turn leadership mistakes into a better future.pptx
 

Mosfet

  • 1. MOSFET I-V Characteristics Contents •Types •Cut off region •Linear region •Saturation region •Comparison •Conclusion and References 1Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 2. Characteristics comes under three category • Cut-off region • Linear region • Saturation region Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 3. MOSFET I-V Characteristics : Cutoff Region •When VGS < VT, there is no channel formed between the Drain and Source and hence IDS=0 A •This region is called the Cutoff Region •This region of operation is when the Transistor is OFF Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 4. MOSFET I-V Characteristics : Linear Region • When VGS> VT, a channel is formed. IDS is dependant on the VDS voltage • When VDS= 0v, no current flows Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 5. • If VGS> VT and VDS> 0, then a current will flow from the Drain to Source (IDS).The MOSFET operates like a voltage controlled resistor which yields a linear relationship between the applied voltage (VDS) and the resulting current (IDS) • For this reason, this mode of operation is called the Linear Region.This region is also sometimes called the triode region (we'll use the term "linear") • VDS can increase up to a point where the current ceases to increase linearly (saturation) • We denote the highest voltage that VDS can reach and still yield a linear increase in current as the saturation voltage or VDSAT Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 6. • when a voltage is applied at VD,its positive charge pushes the majority charge carriers (holes) that exist at the edge of the depletion region further from the Drain. • As the depletion region increases, it becomes more difficult for the Gate voltage to induce an inversion layer. This results in the inversion layer depth decreasing near the drain. • As VD increases further, it eventually causes the inversion layer to be pinched-off and prevents the current flow to increase any further. • This point is defined as the saturation voltage (VDSAT) • From this, we can define the linear region as: VGS>VT 0 < VDS < VDSATPrepared By S ARUN M.Tech MOSFET VI Characteristics
  • 7. Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 8. • The Drain to Source current (IDS) is given by the expression: • Where: un = electron surface mobility (units in cm2 /V·s) Cox = Unit Oxide Capacitance (units in F/cm2 ) W = width of the gate L = length of the gate • Remember this expression is only valid when : VGS>VT 0 < VDS < VDSAT ( )[ ]2 02 2 DSDSTGS oxn DS VVVV L WCu I linear −⋅−⋅⋅⋅ ⋅ = Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 9. • what is linear about this equation? • Most of the parameters are constants during evaluation. They are sometimes lumped into single parameters • Notice that W and L are parameters that the designers have control over. Most of the other parameters are defined by the fabrication process and are out of the control of the IC designer. ( )[ ]2 02 2 DSDSTGS oxn DS VVVV L WCu I linear −⋅−⋅⋅⋅ ⋅ = oxn Cuk ⋅=' ( )[ ]2 02 2 ' DSDSTGSDS VVVV L Wk I linear −⋅−⋅⋅⋅= L W Cuk oxn ⋅⋅= ( )[ ]2 02 2 DSDSTGSDS VVVV k I linear −⋅−⋅⋅= Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 10. • What is linear about this equation? • The -VDS 2 term alters the function shape in the linear region. As it becomes large enough to significantly decrease IDSin this function, the transistor enters saturation and this expression is no longer valid. ( )[ ]2 02 2 DSDSTGSDS VVVV k I linear −⋅−⋅⋅= For a fixed VGS, then IDS depends on VDS VDS 2 has a smaller effect on IDS at low values of VDS since it is not multiplied by anything Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 11. • Since we know what the current will not decrease as VDS increases past VDSAT, we can usethis expression to define VDSAT • when VDS>(VGS-VT), then IDS in this expression begins to decrease • we can then define VDSAT = (VGS-VT) • So now we have the formal limits on the linear region and the validity of this expression: • Linear Region : VGS>VT 0 < VDS < (VGS-VT) ( )[ ]2 02 2 DSDSTGSDS VVVV k I linear −⋅−⋅⋅= Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 12. MOSFET I-V Characteristics : Saturation Region • MOSFET is defined as being in saturation when: Saturation Region : VGS> VT and VDS > (VGS-VT) • An increase in VDS does not increase IDS because the channel is pinched-off • However, an increase in VGS DOES increase IDSby increasing the channel depth and hence the amount of current that can be conducted. • Measurements on MOSFETS have shown that the dependence of IDS on VGS tends to remain approximately constant around the peak value reached for VDS=VDSAT • A substitution of VDS=(VGS-VT0) yields: ( ) ( ) ( )[ ] ( )2 0 2 000 2 2 2 TGSDS TGSTGSTGSDS VV k I VVVVVV k I sat sat −⋅= −−−⋅−⋅⋅= Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 13. 1st order expressions for all three regions of operation for the MOSFET Now we have Region Conditions IDS Cutoff VGS< VT Linear VGS> VT VDS < (VGS-VT) Saturation VGS> VT VDS > (VGS-VT) 0=cutoffDSI ( )2 0 2 TGSDS VV k I sat −⋅= ( )[ ]2 02 2 DSDSTGSDS VVVV k I linear −⋅−⋅⋅= Prepared By S ARUN M.Tech MOSFET VI Characteristics
  • 14. • Conclusion In this presentation conclude that came to know regards VI characteristics of MOSFET. • References  Sedra and smith, “Microelectronic circuits”,7th Ed., Oxford University Press. Thomas L.Floyd, “Electronic devices” Conventional current version, Pearson prentice hall. Robert L.Boylestad, “Electronic devices and circuit theory”,