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> Cars are a really noisy electrical environment. Can you replace that micron-scale chip with a 7 nm chip and have it function reliably for two decades in that

> Cars are a really noisy electrical environment. Can you replace that micron-scale chip with a 7 nm chip and have it function reliably for two decades in that environment? For as long as you talk about digital side, you can. Your smartphone is a way more noisy electrical environment than your car.

xnyan 5y ago
>Your smartphone is a way more noisy electrical environment than your car. Cellphones are are certainly tricky, but in a different way than cars. In my experience with EMF measurement and EMI compliance at Underwriters Labs, cars are uniquely challenging due to the relatively strong EMF generation from the huge number of motors, solenoids, coils other magnetic bits banging around and interacting with each other in hard-to-predict ways.
- baybal2 5y ago
  High voltage CMOS is certainly needed there of course, but you don't put you logic chip on the same die as a motor inverter.
Noted 5y ago
I don't think smartphones are expected to work on the same timescale that a car should.
throwaway9870 5y ago
First, there is no such thing as digital. It is just an abstraction to facilitate our understanding and design of circuits. Any number of issues can cause that abstraction to fail, even deep within a modern chip, let alone at the board level. On-chip cross talk, RC drop, and ground bounce are simple analog issues that have to be contended with on digital designs. Every chip has a power supply and the smaller geometry chips have less tolerance to supply spikes. Same with I/O including voltage range tolerances and ESD protection. All that gets harder in smaller geometries. Also factor in circuit lifetimes (including digital). Due to a variety of mechanisms, small geometry chips just are not as reliable and some of these mechanisms are very hard to accelerate so qualification is a nightmare. A smart phone is not a "way more noisy" environment than a car. It has different issues, and frankly a far more constrained and predictable environment. A load dump event in a car can take the 12V supply over 100V. I have never heard of that in cell phone. Long wiring harnesses are a nightmare and require careful design. It is hard to compare a cell phone and car without a clear definition of "noisy", but as someone who has designed systems similar to both, I think the car is a harder set of problems. Just not as constrained noise sources or components.
InitialLastName 5y ago
Misunderstandings about noise in digital systems and environmental conditions in smartphones vs cars aside (well, no: your phone isn't operating at 100C or vibrating in anything like the way a car does), your smartphone doesn't run reliably (relative to automotive reliability requirements) for a day. When a failure can kill someone, you have to take it much more seriously than when a failure slightly inconveniences a user while they restart the app.

xnyan 5y ago

>Your smartphone is a way more noisy electrical environment than your car. Cellphones are are certainly tricky, but in a different way than cars. In my experience with EMF measurement and EMI compliance at Underwriters Labs, cars are uniquely challenging due to the relatively strong EMF generation from the huge number of motors, solenoids, coils other magnetic bits banging around and interacting with each other in hard-to-predict ways.

baybal2 5y ago
High voltage CMOS is certainly needed there of course, but you don't put you logic chip on the same die as a motor inverter.

Noted 5y ago

I don't think smartphones are expected to work on the same timescale that a car should.

throwaway9870 5y ago

First, there is no such thing as digital. It is just an abstraction to facilitate our understanding and design of circuits. Any number of issues can cause that abstraction to fail, even deep within a modern chip, let alone at the board level. On-chip cross talk, RC drop, and ground bounce are simple analog issues that have to be contended with on digital designs. Every chip has a power supply and the smaller geometry chips have less tolerance to supply spikes. Same with I/O including voltage range tolerances and ESD protection. All that gets harder in smaller geometries. Also factor in circuit lifetimes (including digital). Due to a variety of mechanisms, small geometry chips just are not as reliable and some of these mechanisms are very hard to accelerate so qualification is a nightmare. A smart phone is not a "way more noisy" environment than a car. It has different issues, and frankly a far more constrained and predictable environment. A load dump event in a car can take the 12V supply over 100V. I have never heard of that in cell phone. Long wiring harnesses are a nightmare and require careful design. It is hard to compare a cell phone and car without a clear definition of "noisy", but as someone who has designed systems similar to both, I think the car is a harder set of problems. Just not as constrained noise sources or components.

InitialLastName 5y ago

Misunderstandings about noise in digital systems and environmental conditions in smartphones vs cars aside (well, no: your phone isn't operating at 100C or vibrating in anything like the way a car does), your smartphone doesn't run reliably (relative to automotive reliability requirements) for a day. When a failure can kill someone, you have to take it much more seriously than when a failure slightly inconveniences a user while they restart the app.