I've done whatever I want

Chapter 118 Chip Design Madman
The next day was Sunday, and Little Swallow went to work in the factory early in the morning. After a busy night, when she was ruthlessly woken up by the alarm clock, she was a little sleepy.

The plan to get up and make a love breakfast for Jiang Hua was shattered. She didn't even have time to take care of her fluffy hair, so she opened the door and left.

She usually lives in a dormitory, but when she gets up, she is always as energetic as Monkey King.

After Jiang Hua was promoted to production supervisor, he enjoyed the five-day and eight-hour treatment of a foreign company, sleeping like a dead pig until ten o'clock in the morning.

I was so excited last night that I feel weak now and have some back pain.

With heavy steps, he walked around the community a few times and made an appointment with several landlords to look at the house. With his hands on his hips, he repeatedly emphasized that the co-tenants must have a positive outlook and not be crazy.

"Brother, help me move the pots and pans!" After finding a rental house, Jiang Hua shouted at Xin Tong while packing his things.

"No problem!" Xin Tong said while helping to pack things.

When moving things up the stairs, Jiang Hua panted like a little old man: "I can't do it, I'm exhausted!"

"Brother, do you have kidney deficiency?"

"Don't laugh at me. Production management is no better than your technical skills. Our lives are miserable! We are as busy as an old buffalo plowing fields every day in the workshop. Are you not tired?" Jiang Hua took a break.

"You're talking about the OP operator! You're the production supervisor giving orders, so you're tired!" Xin Tong said with a smile.

"Old classmate, your back hurts when you stand and talk!"

The two tossed for a while, and Jiang Hua's things were moved away. Except for the occasional Buddhist voice, the rental house was quiet.

Xin Tong used to live in a collective dormitory. Although he lived alone, the corridors were not quiet. From time to time, people would run past like thunder, and from time to time, some people drank too much and sang like a broken gong. singing heartless songs.

That's okay, spend some money to rent a house and buy a quiet place, so you can concentrate on your studies.

It takes time to learn Six Sigma Black Belt, and it also takes time to take the self-study exam for undergraduate microelectronics at Shanghai Jiao Tong University.

The reality is too barren, and the ideal is too full. Only by running hard can we break free from the fetters of time.

He sat at the table and flipped through the circuit books carefully.

"Dong dong dong!" In the silence, someone knocked on the door.

Xin Tong opened the door. He knew that the person knocking on the door was Yuan Chengxu. In this rental house, there were only two animals moving around. Who else could it be?

"Xin Gong, you are also studying chip circuits!" Seeing the circuit books on the desk, Yuan Gong was full of curiosity.

This young man is engaged in integrated circuit packaging. How did he start studying chip design?
The distance from packaging to design is far longer than the one hundred and eighty thousand miles traveled by Sun Wukong.

"It's not about research!" Xin Tong smiled faintly.

He found it a bit funny to talk about research in front of a chip design expert.

"Xin Gong, if you have never done chip design, you can't imagine how hard it is!" Yuan Chengxu sighed.

"is it?"

"If you are not prepared to endure great hardship, please do not do chip design! This is my advice to you!" Yuan Chengxu said meaningfully.

"Yuan Gong, even if there are 81 difficulties, you can't stop me!" Xin Tong said.

The hatred of lack of core in the previous life must be revenged in this life!

"If you want to learn chip circuits well, you must spend time thoroughly researching the four elements of the circuit: Input Pair, Current Mirror, Cascode, and Invertor." Seeing Xin Tong's determination, Yuan Chengxu said.

This is a summary of his experience.

Just like the two instruments in the Book of Changes give rise to the four images and the four signs give rise to the Bagua. Once you understand the nature of a circuit, you will dismantle any complex circuit into simple units.

"Thank you Yuan Gong for your guidance!" Xin Tong was full of gratitude.

If there is no teacher to guide him, he will be an ignorant child!

"However, learning the circuit well does not mean that you can design the chip well! To design the chip well, the road is too long!" Yuan Gong said with emotion.

"Really?" Xin Tong was confused.

If the things in the book cannot serve as a guide, they are misleading!
"Chip design, especially analog chips, is more difficult to design. The thinking mode of analog circuits has grayscale, not black and white. Digital circuits are 0 and 1, which are either black or white. Analog circuits have many middle ground ." Yuan Chengxu said.

When Xin Tong heard this, he was very surprised. This Yuan Gong's knowledge and cognition are really superior to others.

"Besides, theoretical things are too perfect. Design is one thing, manufacturing is another. Due to the dispersion of semiconductor device parameters, there is a large deviation. Resistors, capacitors and other components generally have a deviation of more than ±5%. The errors are sometimes even larger. Therefore, blindly pursuing strict calculations does not make much sense." Yuan Chengxu's face was full of helplessness.

"So that's it!" Xin Tong seemed to have some realization.

He has been engaged in motor development in his previous life, and he has also participated in the discussion. His thinking on the tolerance definition and cumulative error of the size of structural parts runs through the entire design verification process.

Yuan Gong is right, the design must take into account the manufacturing, Design for Manufacturing!
Looking back at the motors of the previous life, there are no more than a thousand materials involved in the BOM (Bill of Materials).

Chips are different. There are tens of thousands or hundreds of millions of transistors.

If each transistor has a slight deviation, the accumulated deviation will cause the carefully calculated circuit to become a mess in the end.

"It's not easy to design a chip well!" Xin Tong sighed.

"So, fine calculations will definitely not work! Experience is very important, and simulation testing is very important!" Yuan Chengxu said.

"What is a simulation test?" Xin Tong asked.

"Xin Gong, do you know the design of simple mechanical assembly?"

Xin Tong nodded.

Of course he knew that he was an electrician in the previous generation.

"Mechanical design pays attention to adaptation, Fitness! Sometimes there are too many accumulated tolerances, and the design does not fully consider the tolerances. It can be verified by adaptation. I think simulation verification is a bit like the adaptation of the traditional mechanical design industry!"

Yuan Gong is full of unique insights into chip design.

After his explanation, Xin Tong suddenly understood why it was so difficult for someone as talented as Yuan Gong to handle a chip circuit. At this moment, he finally understood.

"A good chip design engineer must understand PDK!" Yuan Chengxu continued.

"What is PDK?" Just now, he still had a little thought, so Xin Tong felt as if he was in a sea of ​​clouds again, and everything was hazy.

"Xin Gong, the full name of PDK is Process Design Kit, which translates into Chinese as process design kit. PDK contains basic elements that reflect the manufacturing process, such as transistors, contact holes, interconnect lines, etc. It is a communication link between IC design companies, foundries and EDA The manufacturer's bridge is a set of documents that reflect the Foundry process. It is the cornerstone used by design companies to do physical verification, and is also a key factor in the success or failure of tape-out. I have stumbled on this, thinking that if there are no bugs in the circuit, there will be no bugs in the manufacturing. It’s done, and it’s a complete failure!”

When Yuan Gong said this, he looked up at the ceiling and said nothing for a long time.

Where is this doing chip design?This is fighting an unknown monster!
No wonder Yuan Chengxu is crazy and utters some Buddhist voices from time to time. He is a master problem solver, and he loves to overcome difficulties by nature, but the road of chip design is not smooth, so it is strange that he does not hold back and go crazy!
"Amitabha!" Yuan Chengxu suddenly sighed.

　There are some chips with hundreds of millions of transistors on them, and each transistor has errors. Only God knows how difficult it is to combine them into a powerful integrated circuit!

　　Thanks to Qingquan Muyang and Xingxingshuo for their eternal rewards!
　　
　
(End of this chapter)