Today's post is a continuation of the previous post, "About the N-MOSFET" which was about the simple N-MOSFET. If you haven't already checked it out, I highly recommend that you do.
This post is the "First thing's first" type of post so let's start with the 4 basic categories or levels of abstraction into which the vast VLSI field maybe divided.
1.Physical level/Transistor level.
2.Circuits level.
3.Sub-systems level/ Architectural level.
4.Systems level.
In the first category, one learns about all the physical properties of a MOSFET, like what should the physical parameters be, in order to change its electrical parameters. Alongside, (s)he also learns the 4 basic terminals of a MOSFET - Source, Gate, Drain and Bulk. Generally, the bulk terminal isn't considered in initial stages of learning designing concepts. But it comes into picture when one designs advanced circuits. Knowledge of this is a must, and frankly it's a little complex and boring to understand, but it's not a lengthy concept. I'll write another post just on this topic later.
In the Circuits level one first learns how to create the basic gates and then put them together to make simple circuits which can perform simple functions. I'll write about the basic gates (NOT, AND & OR) in the upcoming post. This can be considered analogous to functions in programming, where small functions with minor problem definitions can be created so they can be put together to create a solution for the major problem definition. In this level, one also learns how to design layouts for the circuit developed, using the standard rules of layout design, which is a vast field. Examples for this level maybe CMOS subcircuits, and CMOS amplifiers.
Architecture level deals with the sub-major problem-definition solutions. Here, the circuits developed in the previous levels are put together to make a valid architecture for the sub-solution. Examples maybe CMOS Op-Amp, High level amplifiers, comparators etc. These are put together in the next level in form of a block diagram to create working systems.
The Systems level is similar to designing a block diagram where each block represents the sub-system circuitry. The designer of this level need not know what happens at the electrons level in the transistor. (S)he is just concerned in placing all blocks together so that they work efficiently &/or economically as one whole system. The examples in this level maybe industrially available Analog to Digital converters (ADCs) or Digital to Analog Converters (DACs).
After learning all the four concepts, one has to decide which field interests him/her the most and go ahead in that field. Generally, people recommend that one gains exposure in all of the fields for complete growth in knowledge of VLSI. Also, people usually get started with the verification of developed systems and go on towards R&D in either of the four categories.
I'll come up with another post which can elaborate on real time examples of these 4 levels so the reader finds it easy to understand and gets motivated to learn theory regarding it. Of course, the post will come up after I have elaborately explained the above levels of abstraction.
This post is the "First thing's first" type of post so let's start with the 4 basic categories or levels of abstraction into which the vast VLSI field maybe divided.
1.Physical level/Transistor level.
2.Circuits level.
3.Sub-systems level/ Architectural level.
4.Systems level.
In the first category, one learns about all the physical properties of a MOSFET, like what should the physical parameters be, in order to change its electrical parameters. Alongside, (s)he also learns the 4 basic terminals of a MOSFET - Source, Gate, Drain and Bulk. Generally, the bulk terminal isn't considered in initial stages of learning designing concepts. But it comes into picture when one designs advanced circuits. Knowledge of this is a must, and frankly it's a little complex and boring to understand, but it's not a lengthy concept. I'll write another post just on this topic later.
In the Circuits level one first learns how to create the basic gates and then put them together to make simple circuits which can perform simple functions. I'll write about the basic gates (NOT, AND & OR) in the upcoming post. This can be considered analogous to functions in programming, where small functions with minor problem definitions can be created so they can be put together to create a solution for the major problem definition. In this level, one also learns how to design layouts for the circuit developed, using the standard rules of layout design, which is a vast field. Examples for this level maybe CMOS subcircuits, and CMOS amplifiers.
Architecture level deals with the sub-major problem-definition solutions. Here, the circuits developed in the previous levels are put together to make a valid architecture for the sub-solution. Examples maybe CMOS Op-Amp, High level amplifiers, comparators etc. These are put together in the next level in form of a block diagram to create working systems.
The Systems level is similar to designing a block diagram where each block represents the sub-system circuitry. The designer of this level need not know what happens at the electrons level in the transistor. (S)he is just concerned in placing all blocks together so that they work efficiently &/or economically as one whole system. The examples in this level maybe industrially available Analog to Digital converters (ADCs) or Digital to Analog Converters (DACs).
After learning all the four concepts, one has to decide which field interests him/her the most and go ahead in that field. Generally, people recommend that one gains exposure in all of the fields for complete growth in knowledge of VLSI. Also, people usually get started with the verification of developed systems and go on towards R&D in either of the four categories.
I'll come up with another post which can elaborate on real time examples of these 4 levels so the reader finds it easy to understand and gets motivated to learn theory regarding it. Of course, the post will come up after I have elaborately explained the above levels of abstraction.
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