Electronics Simulations #13| Characterization of a MOSFET by using Caneda

What Will I Learn?

In this tutorial, reader:

• will learn the regions of MOSFETs
• will learn how to take characterization graphics of MOSFETs
• will learn how to find characterization of MOSFET in Caneda

Requirements

To complete the tutorial, readers would have:

• basic knowledge about MOSFETs
• basic knowledge about Caneda software

Difficulty

• Intermediate

Tutorial Contents

In this tutorial, I am going to find characterization of a NMOS by using circuit simulator Caneda.I will start with giving basic knowledge about regions of MOSFETs, then construct the circuit on Caneda and as a last step, I will observe simulation results. Let me start with explaining basics of MOSFET regions.

- Episode 1: Working Regions of MOSFETs

MOSFETs are generally observed in two different graphics, which are Ids(Drain to source current) vs Vgs (Gate to Source voltage) and Ids (Drain to source current) vs Vds (drain to source voltage). An expected graphs should look like:

_{Source of the image}

First figure shows Ids vs Vgs where second one shows Ids vs Vds. We can say that to operate a MOSFET, we have to bias Vgs with a Vt(terminal voltage), without that bias, MOSFET will not work.

And also we can change working regions of MOSFETs by playing with Vds. As we can see from the second graph, when we increase Vds sufficently, we move to saturation region from the ohmic region. Functions of that regions are given below:

Cut-Off Region:

Cut-off region is a region in which the MOSFET will be OFF as there will be no current flow through it. In this region, MOSFET behaves like an open switch and is thus used when they are required to function as electronic switches.

Ohmic or Linear Region:

Ohmic or linear region is a region where in the current IDS increases with an increase in the value of VDS. When MOSFETs are made to operate in this region, they can be used as amplifiers.

Saturation Region:

In saturation region, the MOSFETs have their IDS constant inspite of an increase in VDS and occurs once VDS exceeds the value of pinch-off voltage VP. Under this condition, the device will act like a closed switch through which a saturated value of IDS flows. As a result, this operating region is chosen whenever MOSFETs are required to perform switching operations.

- Episode 2: Constructing the circuit on the software

The circuit that I am going to construct is given below:

_{Source of the image}

I will skip the basics of construction steps, since I have already explained it in previous tutorial.

The main thing is here to control both sources with DC sweep function as shown below:

Reader should put the corresponding parameter for x axis to source parameter not source2 parameter. This is the main difference on the graphs that I am going to show. Please note that I am sweeping both voltage sources.

- Episode 3: Simulation and obtaining characteristics

All we need to do is to save the circuit and start simulation button. The first result should look like(When we are sweeping VV2 which is Vds):

X axis corresponds to Vds

Y axis corresponds to Ids

The second parameter naming(When we are sweeping VV1 which is Vgs):

In this case we put Vgs to X axis. The result should look like:

Which corresponds Ids vs Vgs graph.

X axis corresponds to Vgs

Y axis corresponds to Ids

So we have managed to characterize our MOSFET.I have proven that circuit works as we desire, so we have managed to obtain MOSFET on Caneda software.

I have provided the files for this tutorial here. I highly recommend that the reader should work on the files that I have provided and try to understand the basics of the circuit & software. It will be benefical for he/she.

This is the end for this tutorial.Hope that you like it.

Caneda software is really user-friendly & effective for the one who wants to make simulation. If you have any questions, please feel free to ask me on Discord (Escorn#4114)

Sources

Source for the MOSFET basics

Source for the circuit

Curriculum

I have provided the previous tutorials that I have prepared for the community:

SimulIDE	Caneda
Part 1	Part 1
Part 2	Part 2
Part 3	Part 3
Part 4	Part 4
-	Part 5
-	Part 6
-	Part 7

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Posted on Utopian.io - Rewarding Open Source Contributors

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