The topic of this assignment is to assess on various kinds of IC design. Therefore, we must first understand this is of IC. An IC, integrated circuit, can be known as microcircuit, microchip, silicon chip, or chip. It really is a small electronic circuit that contains semiconductor devices and other passive components. These elements are made on a ceramic or plastic container. Internal connections happen to be welded from the chip to numerous number of external pins depending on the chip’s function.

IC design signifies that employing logic and circuit design and style techniques to design and produce integrated circuits. It requires pathways to ensure that information can flow correctly and small electrical parts are organized to increase space so that personal computers is often as small as possible. Living in this modern age of data information, we have to design faster and more compact IC to increase our daily life quality and meet up with the technology.

IC style is classified generally into two categories of analog and digital IC design. Digital IC design is the most widely used in daily life such as for example microprocessor, FPGAs, remembrances (RAM, ROM, and flash) and digital ASICs. Alternatively, analog IC is employed in the design of sensors, power control circuits, and operational amplifiers.

The body of IC is displayed below :

Figure 1(a) Figure 1(b)

(Adapted from introduction to ASIC, http://iroi.seu.edu.cn/books/asics/Book2/CH01/CH01.htm [1])

Figure 1(a) displays an IC chip where in fact the pins will match holes in a printed-circuit plank or breadboard. Figure 1(b), the silicon chip (more properly referred to as a die) is fitted in the cavity beneath the sealed lid.

A more detail classification of IC based on digital and analog is as follow :

Chart 1 : Hierarchical classification of IC

Referring to chart 1, as we are even more interested in the branch of digital IC design, I expand considerably more on its hierarchy review to others. I am going to first assess between analog and digital IC design. Then I will explain on the benefits of all of them and mixed-signal IC design. Next, I will compare and describe on full custom and semi-tailor made IC follow by a straightforward description of silicon compilation as it is not discussed in lectures. From then on, I will compare gate array, regular cell and PLDs.

Content

Analog, digital and mixed signal IC design

The comparison between analog and digital IC style is tabled as below :

Characteristics

Analog IC design

Digital IC design

Noise

More susceptible to noise

Less noise

Precision

Less precise

More precise

Design difficulty

Harder to design

Easier to design

Complexity

High

Low

Power consumption

Low

High

Heat dissipation

Low

High

Design work

Demands strong knowledge of the principles, concepts and techniques

done by copying and reusing the same circuit features or library

Life cycle

10years

1 to 2 years

Cost

Low

High

Information storage

Noise from ageing degrades information

noise-immunity makes information certainly not degraded

Table 1 : Evaluation between analog IC design and digital IC design

Analog IC design

In analog IC design, the analog indicators take any value from a given range, and each one of a kind signal value represents different information. It is normally within op-amps, linear regulators, period locked loops, oscillators and effective filters. Therefore, a slight change in the signal may affect the design. For example, an analog signal is utilized to represent heat, with one volt representing one level Celsius. As a result, 10 volts would generate 10 degrees, and 10.1 volts would produce 10.1 degrees. Analogue IC design and style produces noise, which is a random disturbance, variation or random thermal vibrations of atomic particles. Since any changes within an analogue signal can be significant, any disturbance changes in the original signal and appears as noise. As the signal is definitely copied and re-copied, or transmitted over lengthy distances, these random variants are more significant and result in signal degradation. Other sources of noise can include external electrical indicators or poorly designed factors. These disturbances are lowered by shielding, and employing low-noise amplifiers.[2] Nevertheless, some irreducible noise such as the shot noise in parts will make an analog IC design and style imprecise. When designing an analog circuit, the choice of every single component, size, placement, and connection is vital. Every small detail such as the resistance, placement and quantity of resistor, will affect the performance of end result. Therefore, designing an analog IC needs strong knowledge of the principles, ideas and techniques. Hence, it is said that analog IC design and style is much more complex review to digital IC design and style. It is harder to create because analogue circuit must be designed by hand, and the procedure is much less automated than digital IC. However, once an analog IC was created successfully with high transmission to noises ratio, low distortion, low power consumption, high dependability and stability, it could have a life cycle greater than 10 years. As a result of the long life cycle, the cost of analog IC is normally low.

Digital IC design

A digital IC was created to accept only suggestions voltages of specific ideals and it uses only two states which will be the binary amounts, "on" and "off" representing 1 and 0 or "true" and "false". That is achieved by applying the logic of Boolean algebra. The three basic logic functions in an electronic IC are NOT, AND, and OR. A truth table is required to design a digital IC. As mentioned in the lectures, the design of digital systems is split into combinational systems, that is a representation of a set of logic functions, and sequential devices, which are state equipment. It is often within microprocessors, FPGAs, recollections (RAM, ROM, and flash) and digital ASIC.

Digital IC design and style produces less noise and even no noise. Digitally represented signals are transmitted employing binary sequence of 1 1 and 0. It is usually reconstructed, retransmitted or transmitted over very long distance without the error provided the noise during transmission is unable to alter the 1s and 0s. Hence, digital IC is extra precise compare and contrast to analog IC. Possibly in a concise disc of around 6 billion binary digits, the info or data could be presented specifically because each digit is usually taken care of by the same kind of hardware and there is absolutely no noises in the handling process. Digital IC is simpler to design because it is handled by software such as electronic design automation equipment (EDA) in order that functions can be altered without changing the hardware. If consumers find error, they are able to simply upgrade the program to rectify the mistake. As digital IC is almost immune to noise, data can be kept and retrieved totally and precisely without the damage or degradation.

However, there are a few down sides of digital IC. Because digital IC is quite dense in circuitry, digital circuits make use of more energy than analog circuits to perform the same tasks, therefore creating more heat. In portable or battery-powered

systems this may limit use of digital systems.[3] Digital IC emphasizes on speed and expense ratio computing to attain the lowest possible cost with the best operating acceleration. Designers must use more efficient algorithms to plan digital indicators, or use new method to increase the integration cost. Therefore, the life span cycle of digital IC is quite short, about 1 year -2 years and the cost is greater than analog IC.[4] Since digital circuits involve millions of times as many elements as analog circuits, a lot of the design work is done by copying and reusing the same circuit functions, especially by using digital design software that contains libraries of pre-structured circuit components. [5]

Mixed signal IC design

A mixed-signal included circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die.[6] Mixed-signal can be found in ADC or DAC and digital radio chips. Since mixed-transmission IC necessitates both analog and digital design and style, it is generally designed for an extremely specific purpose and as a result of that, their design takes a higher level of expertise and very careful usage of computer aided design (CAD) tools. Therefore this kind of design is very complicated andcostly.

Full-custom and semi-tailor made IC design

The assessment between analog and digital IC design and style is tabled as below :

Characteristics

Full-custom IC design

Semi-custom IC design

Circuits

Customized

Predesigned how to write a technical paper with no mistakes

Manufacturing time

Long

Short

Performance

Maximize

Moderate

Area of IC

Minimize

Moderate

Cost

High

Low

Table 2 : comparison between full-custom and semi-custom IC design

Full-custom IC design

Full-custom design can be a methodology for developing included circuits by specifying the design of each individual transistor, logic cells, mask layers and the interconnections between them.[7] Basically, the IC was created from scratch and tailor-made to meet up the requirement of a particular purpose. The primary goal of experiencing a full-custom design and style is to maximize the effectiveness and minimize the region of an IC. Consequently, a whole lot of researches and studies are needed to produce a full-tailor made IC which results in high production cost and very long manufacturing period. Usually, full-tailor made IC is normally catered for large production in order that the high production price is fully utilized. Full-custom made IC is produced from time to time when there is absolutely no suitable existing libraries obtainable that works extremely well for the design. For the reason that existing libraries happen to be outdated or consume an excessive amount of power.

Semi-custom IC design

Semi-custom IC design could be partly custom-made to serve different features within its general region of application.[8] It allows a certain extend of modification during the manufacturing process. It has the diffused layer completely defined but the libraries of pre-structured circuit parts with the same circuit capabilities can be reused. This can save considerable time and expense to in producing a semi-custom IC design and style. Therefore, the manufacturing price if low and it is used widely in almost every IC design around the globe. Semi-custom IC style is further classified into 3 teams which will be gate array, common cell and programmable logic units circuits.

Silicon compilation IC design

Silicon compilation is by using a software system that requires a user’s specifications and instantly generates an integrated circuit (IC).[9] Generally, a creator is given a information of the machine, by using a silicon compiler, mask and test facts are produced which is definitely either a straightforward combinational circuit or a finite talk about machine. The first step of silicon compilation is definitely Convert a hardware-description words such as for example Verilog or VHDL or FpgaC into logic. Subsequent, we will place the logic gates on the IC followed by routing the typical cells together to create the required logic.[9] A drawback of this method of IC design and style is that almost all of the silicon https://testmyprep.com/lesson/how-to-write-a-good-persuasive-essay compilers do not utilize the region of silicon efficiently. So, it is usually produced in small volume. It could used to generate simple cells to develop standard cell libraries.[10]

Gate array, normal cell and programmable logic equipment (PLDs) IC

The evaluation between gate array, standard cell and programmable logic devices circuits is tabled as below :

Characteristics

Gate array

Standard cell

PLDs (FPGA)

Flexibility

Flexible

Very flexible

Less flexible

Risk

Less risky

Less risky

Risky

Manufacturing Cost

Moderate

Cheap

Expensive

Manufacturing Difficulty

Moderate

Easy

Very complex

Manufacturing time

Shortest

Short

Moderate

Silicon size

Moderate

Small

Limited

Speed

Slow

Moderate

Fast

Heat dissipation

Low

Moderate

High

Table 3 : Comparison between gate array, normal cell and PLDs (FPGA) IC

Gate array IC

In a gate-array-structured IC, the transistors, logic gates and additional active devices happen to be predefined on the silicon wafer. The only uncompleted portion of the creation may be the final surface coating, which defines the interconnect between your elements. Connecting these components permits the function of the IC to end up being customized. Therefore, it is extremely flexible and less risky because it uses predefined factors. Furthermore, adding a area layer of interconnects requires simply a tiny cost and small amount of time to complete. Even so, the chips designed using gate array tactics are a little bigger in silicon region than standard cell IC, which makes them more expensive and harder to produce.[11]

Standard cell IC

In typical cell IC, numerous sizes of predesigned cells are used and a big mixture of cells could be formed which is known as mega cells. Mega cells can be found in microcontroller or microprocessor. These cells, which contain logic functions such as gates, latches, buffers and flip-flops, are referred to as standard cell library. Custom only must define only the keeping the standard cells and the interconnects in a standard cell IC.[12] Common cell IC is versatile because it uses both digital and analog capabilities. The transistor sizes can be changed to boost speed and effectiveness. It includes a smaller silicon size and therefore a more compact happen to be compare to gate array IC. In addition, it has faster velocity which results in higher heat dissipation.

(Adapted from Standard-Cell-Based ASICs, http://iroi.seu.edu.cn/books/asics/Book2/CH01/CH01.1.htm#pgfId=1331)[1]

Figure 2 shows A cell-founded IC die with an individual standard-cell area (a adaptable block) together with four fixed blocks.

Programmable logic devices IC

PLD can be an electronic component used to build reconfigurable digital circuits an undefined function during manufacture.[13] Before starting to apply PLD in a circuit, it should be configured or programmed to make a part customized to a specific program. This makes PLD a very flexible design to fulfill any custom specification. On the other hand, the limited size (<10000 comparative gates) of PLD IC helps it be not as versatile as array gate or typical cell IC. Since PLD can only be modified using program, it cannot possess any last-minute design changes. The equipment to produce a PLD IC is definitely low-priced but large devices could be expensive to the level of several hundred dollars per chip. Since PLD IC is very compact and operates in high speed, it produces a significant amount of heat concurrently.

(adapted from Programmable Logic Equipment, http://iroi.seu.edu.cn/books/asics/Book2/CH01/CH01.1.htm)[1]

Figure 2 reveals a PLD die. The macrocells commonly contain programmable array logic followed by a flip-flop or latch. The macrocells are connected using a big programmable interconnect block.