Terminals in MOSFET

Introduction of Field Effect Transistors Distinction between a BJT and FET Junction Field Effect Transistor (JFET) N Channel JFET Summary of JFET Operation Mutual or Transfer Characteristic of n-channel JFET Amplification Factor 𝝁 Definition of Parameters p-Channel JFET

Introduction of Metal Oxide Semiconductor Field Effect Transistor - Mosfet Terminals in MOSFET Physical structure of MOSFET MOSFET Working Operation Summary of Operation MOSFET - N Type MOSFET Operation How does Drain current flow MOSFET operation More about Threshold Voltage Current vs Voltage Characteristics - Derivation Non Ideal Current -Voltage Effects or Second Order Effects Short Channel Effects MOSFET Device Capacitances MOSFET Large and Small signal Model pMOSFET Small SIgnal Model To use MOSFET device as a Capacitor nMOSFET as Capacitor- Working

Single Stage Amplifiers Common Source CS Stage with Diode-Connected Load Circuit to measure the Equivalent Resistance Common Drain Stage or Source Follower Common Gate Amplifier Large Signal Behavior Calculation of Input Resistance of a Common Gate Stage

Inverter with Enhancement n- Type MOS as Load Inverter with Linear Enhancement Type Load

Terminals in MOSFET

Previous Page

Next Page

The MOSFET is a four terminal device and the terminals are:

GATE
DRAIN
SOURCE and
BODY or SUBSTRATE

The Terminal Body or Substrate is generally internal to the device and is connected to the Source terminal.

As has been discussed earlier the MOSFET is either an N - Channel MOSFET or a P- Channel MOSFET.

There are two basic forms of MOSFET available:

ENHANCEMENT Type MOSFET
DEPLETION Type MOSFET.

Enhancement Type Mosfet:

The Enhancement Type MOSFET Transistor requires a Gate-Source Voltage VGS to switch ON the device.
The Enhancement Type MOSFET Transistor is equivalent to a Normally Open Switch.

Depletion Type Mosfet:

The Depletion type MOSFET Transistor requires a Gate - Source Voltage VGS o switch OFF the device.
The Depletion type MOSFET Transistor is equivalent to a Normally Closed Switch

Symbols Of Mosfet:

The symbols for the MOSFET for both Enhancement Type and Depletion Type MOSFET are shown in the figures 1 and 2 below:

Note:

The terminal Substrate is connected to the Source terminal.
It may be noted from the Figure 2 above that in Depletion Type MOSFET symbol, the line representing the Drain and Source connections is Thick
It may be noted from the Figure 1 above that in Enhancement Type MOSFET symbol, the line representing the Drain and Source connections is Thin
The Terminal Substrate is neither connected neither to the input nor to the output, but is used for grounding.
It is connected to the main semiconductor channel through a diode junction to the body or metal tab of the MOSFET.
The terminal Substrate is generally connected to the Source Terminal as it is at the lowest potential.

Normally -On Transistor :

The Depletion Type MOSFET is the same as a Normally -On Transistor. This is so because Drain current flows in the MOSFET even in the absence of any Gate biasing or potential i.e. VGS =0

Normally -Off Transistor :

The Enhancement Type MOSFET is the same as a Normally -Off Transistor. This is so because NO Drain current flows in the MOSFET when no Gate biasing or potential is applied i.e. VGS =0

Previous Page

Next Page

Terminals in MOSFET

Field Effect Transistors

Field Effect Transistors

Metal Oxide Semiconductor Field Effect Transistor - Mosfet

Metal Oxide Semiconductor Field Effect Transistor - Mosfet

Amplifiers

Amplifiers

Inverters

Inverters

Terminals in MOSFET