What is the difference between digital IC design and analog IC design? Many newcomers don't know how to choose?
Digital IC design and analog IC design are actually two different directions.
Those who like challenges and like to analyze the specific circuit composed of MOS tubes visible on the computer screen can choose analog IC design. Those who do not reject programming, those who have no fear of programming, and those who hate formula derivation and analysis can choose digital IC design.
The design threshold of analog circuits is high, while digital ICs are designed with computer aids, and their application fields are not completely the same.
If you are a person who likes to concentrate on digging out details in one direction, is determined, and has the spirit of in-depth research in a field, you can choose simulation.
If your personality is someone who likes to dabble in a lot of knowledge and solve practical problems together, you can choose digital IC design.
The difference between the two : digital circuit ICs are devices that process digital signals, such as CPUs, logic circuits, etc.; while analog circuit ICs are devices that process and provide analog signals, such as operational amplifiers, linear regulators, reference voltage sources, etc., they All belong to analog IC.
The signals processed by analog ICs are continuous and can be converted into sine waves for research, while digital ICs process discontinuous signals, which are all pulsed square waves.
Although both digital ICs and analog ICs are chips, they have completely different division of labor and skill requirements for engineers.
Analog IC
Requirements : Analog integrated circuits require everyone to have a very good foundation and a good understanding of the process. This is actually similar to RFIC, but it is not as high in frequency as RFIC. Analog IC has a greater workload than RFIC, but the most important thing is to Only with a very good foundation and years of experience can it be done smoothly and high-performance analog IC products can be produced, otherwise analog ICs will not be called art.
Digital IC
Requirements : Have a good digital circuit foundation and a certain analog circuit foundation, have strong programming ability, have a good impression of EDA tools, be familiar with basic digital IC design process and use of various EDA software, familiar with interfaces, protocols, Algorithms, structures, etc.;
Subdivision of jobs
Analog IC: analog design, analog layout
Digital IC: front-end design, functional verification, DFT design, back-end design
Digital IC Design
Digital IC design is divided into front-end, verification, and back-end. Large-scale teams will also have professional roles such as algorithms, timing, and DFT.
Digital front-end designer
Digital front-end design is at the front end of the digital IC design process, and is a type of digital IC design post. Mainly responsible for the formulation of technical specifications for chip systems, digital modules and digital-analog hybrid interfaces, system prototype verification solutions, and chip system integration solutions;
Responsible for the release and version maintenance of the detailed design, simulation, user manual, verification scheme and test guide of the chip system, digital module and digital-analog hybrid interface.
Digital verification engineers
use software methods to verify that the logic functions defined by the front-end designer meet the target requirements. Digital chips have grown to be very complex today, and over the past decade, the verification function has been separated from the front-end design and an independent methodology has been developed.
This position requires good programming skills, and the method used is close to that of software engineering.
DFT engineer
DFT is the abbreviation of design for test (design for testability), which is to add testability logic in the chip design process. Some companies attribute this position to front-end design, while others attribute it to mid-end implementation.
DFT mainly adds testability logic to the chip, waits for the chip to be manufactured, and tests the chip through the testability logic on the ATE (Automatic Test Equipment, automatic tester) equipment, picks out chips with manufacturing defects and eliminates them. Good chips free of manufacturing defects are left.
Digital back-end designer
The main job of a digital chip back-end engineer is to receive the code submitted by the digital front-end, and finally deliver a complete chip layout and routing result.
It is a technology that combines the beauty of form with the requirements of engineering practice. The beauty of form comes directly from functional content and requirements. In the link of back-end design, tens of thousands of standard units are scattered like stars, but on the premise of satisfying functions and timing, we seek the dependence between each Block. Relationship, and then make the inside of the chip appear harmonious and stable.
This position requires a high level of proficiency in EDA tools, and relatively frequent updates to advanced technology knowledge.
Analog IC Design
Analog IC designers
start with a single transistor and proceed to circuit design, giving a complete circuit diagram. Unlike digital, analog ICs often do not require a high degree of integration, but focus on delicate circuit structures.
This requires designers to have an in-depth understanding of the principles of analog circuits, adopt appropriate circuit structures, define specific device parameters, adjust circuit parameters through EDA software simulation, and have a certain understanding of devices and manufacturing processes.
Analog Layout Designer
The main work content of an analog layout engineer is responsible for layout planning. Specifically, a certain amount of practical experience in full-custom module layout design is required, and they can independently carry out layout planning, design or verification, etc., and undertake the work of block level layout design, improvement and maintenance.
Compared with other positions, the entry threshold of simulation layout is lower, and you can enter the industry after some professional training, but layout is also a job with a very wide range of knowledge, and it is relatively difficult to be a senior and proficient.
Prospects
Thanks to the larger market size and endless application scenarios, the job demand for digital IC design is more than that of analog IC design.
However, digital IC positions are more subdivided. The job content of front-end, verification, and back-end is not small, and it is not easy to change jobs. Newcomers still need to subdivide and choose. In terms of job requirements in the current industry, verify > front-end > back-end .
For simulation, you only need to make a choice between circuit design and layout design, because the thresholds and requirements of these two roles are quite different, and the choice is relatively clear.
Due to the vast space for domestic substitution of analog ICs, although the demand for domestic jobs is also expanding, it is only slightly inferior to digital ICs.
Salary comparison (reference):
At present, as far as fresh graduates are concerned, under the same academic qualifications, the salary difference between the two is not too big (for design), and the salary fluctuation range is basically between 30-60W.
If you have to make a comparison, the current salary of analog IC is slightly higher than that of digital IC: if you graduate in the later stage and have a master’s degree in analog design, the salary in Shanghai is 42W+, and in cities like Chengdu, Xi’an, Wuhan, etc., the salary is about 35W+, the above is only for refer to.
Regardless of whether it is digital IC or analog IC, if students want to enter the industry, they should understand the job division of chip design clearly, compare their own areas of expertise, identify the direction, concentrate on learning and accumulate project experience is the most important.
If you have some confusion and intention about entering/changing careers, or want to know about the project and obtain learning materials for free, the teacher will answer any questions about changing careers for you.
Here is an entry: IC entry guide