Simulation of an N-MOS inverter using
TINA spice software
BY
Sidharth Sajan – 108118094
Srivatsan Sridhar – 108118098
Syed Maaiz - 108118102
B. Tech
In
Electronics and Communication Engineering
NATIONAL INSTITUTE OF TECHNOLOGY
TIRUCHIRAPPALLI-620015
ACKNOWLEDGEMENTS AND ABSTRACT
We would like to thank the Department of Electronics and Communication
Engineering for providing us with an opportunity to gain knowledge on
‘Devices and Networks’, and the applications aspect of this subject, and
knowing the thorough working principle of the project we have taken up.
We would also like to thank our faculty for giving us this opportunity to
explore more in this domain. This project has been a learning experience
for all of us.
The basis of this project is to simulate the working of an N-MOSFET
inverter. The simulation is done using the TINA spice software. The ac
transient response and ac transfer characteristics were recorded and
graphed for a specific signal type.
THEORY
N-MOSFET:
MOSFET stands for Metal Oxide Silicon Field Effect Transistor or Metal
Oxide Semiconductor Field Effect Transistor. This is also called as
IGFET meaning Insulated Gate Field Effect Transistor. The FET is
operated in both depletion and enhancement modes of operation. It is
used as an amplifier in this circuit. It consists of 4 terminals source,
drain, gate, and substrate. The MOSFET works by electronically varying
the width of a channel along which charge carriers flow (electrons or
holes). The charge carriers enter the channel at source and exit via the
drain. The width of the channel is controlled by the voltage on an
electrode is called gate which is located between source and drain. It is
insulated from the channel near an extremely thin layer of metal oxide.
There are two types of MOSFET: P-channel, N-channel. N-channel
MOSFETs are those where the gate region is a doped n-type
semiconductor. We have used an N-channel 2N6755.
CIRCUIT DIAGRAM OF AN N-MOS INVERTER:
Circuit diagram for graphing the AC transient response
Circuit diagram for graphing the DC transfer characteristics
WORKING OF AN N-MOS INVERTER:
N-type metal-oxide-semiconductor field effect transistor inverter
logic uses n-type MOSFETs (metal-oxide-semiconductor field-effect
transistors) to implement logic gates and other digital circuits. These N-
MOS transistors operate by creating an inversion layer in a p-
type transistor body
The MOSFETs are n-type enhancement mode transistors, arranged in a
so-called "pull-down network" (PDN) between the logic gate output and
negative supply voltage (typically the ground). A pull-up (i.e. a "load" that
can be thought of as a resistor, see below) is placed between the positive
supply voltage and each logic gate output.
Any logic-gate, including the logical inverter, can then be implemented by
designing a network of parallel and/or series circuits, such that if the
desired output for a certain combination of Boolean input values
is zero (or false), the PDN will be active, meaning that at least one
transistor is allowing a current path between the negative supply and the
output. This causes a voltage drop over the load, and thus a low voltage
at the output, representing the zero.
SIMULATION USING TINA SPICE:
The purpose of using the TINA SPICE software was to simulate the
circuital model and to observe its behaviour, that is its transient
response and its ac transfer characteristics.
We used a unit step signal of amplitude 5V for the ac source function
generator.
The corresponding transient response showed an inverted unit step
signal with an amplitude of -5V with the same starting time.
For the purpose of graphing the transfer characteristics, a DC source
was used instead of the AC source
The DC transfer characteristics were like an ordinary N-MOSFET.
Transfer characteristics of an N-channel MOSFET
TRANSIENT RESPONSE OF N-MOS INVERTER
DC TRANSFER CHARACTERISTICS OF AN N-MOS
INVERTER
