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> For instance there is no need for a 5nm power management chip But like what if you did it anyway? I remember pondering this while looking at some guitar peda

by cnasc 5y ago

> For instance there is no need for a 5nm power management chip But like what if you did it anyway? I remember pondering this while looking at some guitar pedal schematics. A lot of them use ICs that are basically ancient. Do newer processes have anything to offer (even if it wouldn’t be cost-efficient)?

bserge 5y ago
Cost efficiency is the key, though. It'd be kind of like newer 2.5" SSDs, the actual drive takes up a fraction of the space inside. Just without the benefit of being cheaper. Power savings would pale in comparison to cost and for many components like amps, bigger = more power.
lmilcin 5y ago
For these kinds of chips there is usually nothing the new process can offer other than higher development costs, higher production costs, longer cycle times, lower yields, higher noise levels and higher EMC susceptibility. A chip that fits its package comfortably at 180nm will not benefit from converting it 5nm process at all. The main reasons to get with a smaller process node is to put more transistor on the same area, use less power or reduce the size of the chip, that's it. A power management chip does not qualify. There is one more reason: if you are already invested in smaller process node or when it is difficult to find machinery for older process.
- deleted 5y ago
  [deleted]
bsder 5y ago
No. Especially not for something like guitar pedals. First, you are very likely "pad limited", the pads to connect the chip to the package are much larger than the actual active chip area. Second, newer processes are rarely better at analog-type things. Leakage is worse, noise is worse, etc. Generally, you have to add to the transistor "length" (minimum dimension) in order to get back analog performance parameters. Third, newer processes have to run at really small power supply voltages. Old-school metal gate CMOS in 0.5um or larger was good to 18V+--really good for things like guitar pedals. If you have the tools, you'd be better off doing a guitar pedal in a very old technology.
- userbinator 5y ago
  First, you are very likely "pad limited", the pads to connect the chip to the package are much larger than the actual active chip area. I remember doing the maths for this a while ago, and I believe on a 22nm process you could fit an entire 486 (1.2M transistors) in the area of a single bond pad needed for the later CPUs.
- squarefoot 5y ago
  > If you have the tools, you'd be better off doing a guitar pedal in a very old technology. The parent poster probably refers to BBD delay lines such as the MN3007 and similar devices, whose awful fidelity and noise characteristics made them famous and very recognizable in old music, especially from the 70s. Emulating them in digital is doable, but that requires more complex circuitry. If one could fit a BBD delay line and its clock generator, plus a LFO and a few low noise opamps on the same die, it would be possible to create delay based (echo/flanger/phaser/chorus etc.) pedals at extremely low costs.
bin_bash 5y ago
They actually can be worse in the case of space travel. You get outside the atmosphere and the sun can cause a lot of problems with newer chips. https://www.theverge.com/tldr/2021/3/2/22309412/nasa-perseverance-mars-rover-processor-cpu-imac-1998 https://www.theverge.com/tldr/2021/3/2/22309412/nasa-perseve... Of course this isn't a problem most of us will ever deal with but I still think it's interesting.
marcan_42 5y ago
You literally can't do it. The smaller the process node, the smaller the voltage you can handle and the more delicate the chip is. At 5nm you can't even make USB transceivers; Apple M1 machines had to use external level converters for all the USB ports for this reason.
hristov 5y ago
The thing about power chips is that smaller feature size is not necessarily a good thing. With logic chips, you are essentially moving data and doing math. And you have electrons here and there representing data. It does not matter how many electrons represent a particular bit of data, as long as they can do it reliably. If you can get your feature sizes smaller and have one hundredth of the electrons represent the same bit -- good for you. As long as the data is correctly stored and the math is correct , the fewer electrons the better. Similarly it does not matter what voltage these electrons are kept at. As long as you can tell ones from zeros and can do the math correctly, the lower voltage, lower power and lower heat dissipated - the better. It is different with power electronics. There often you have to provide a certain amount of power to actually move something, or make a motor turn, or make a speaker make sound, etc. So the amount of current and/or voltage your chips produce will actually matter. Say you have a guitar amp. What if someone told you that at a great cost, they could make the chips at that amp a hundred times smaller. They would of course provide a hundred times less power which would make your speaker a hundred times more quiet (well, 2 db, but you get the idea). Would that be a good deal? Not really. That is why analog and power firms like ON Semi (mentioned in the article) tend to look for old equipment. They do not need everything this small. Many of their chips actually require larger features because they have to move a lot of current and/or handle high voltages. But that does not mean that their chips are old technology. Not all innovation is making things smaller. There is plenty of innovation going at the larger sizes.

by cnasc 5y ago

bserge 5y ago

Cost efficiency is the key, though. It'd be kind of like newer 2.5" SSDs, the actual drive takes up a fraction of the space inside. Just without the benefit of being cheaper. Power savings would pale in comparison to cost and for many components like amps, bigger = more power.

lmilcin 5y ago

For these kinds of chips there is usually nothing the new process can offer other than higher development costs, higher production costs, longer cycle times, lower yields, higher noise levels and higher EMC susceptibility. A chip that fits its package comfortably at 180nm will not benefit from converting it 5nm process at all. The main reasons to get with a smaller process node is to put more transistor on the same area, use less power or reduce the size of the chip, that's it. A power management chip does not qualify. There is one more reason: if you are already invested in smaller process node or when it is difficult to find machinery for older process.

deleted 5y ago
[deleted]

bsder 5y ago

No. Especially not for something like guitar pedals. First, you are very likely "pad limited", the pads to connect the chip to the package are much larger than the actual active chip area. Second, newer processes are rarely better at analog-type things. Leakage is worse, noise is worse, etc. Generally, you have to add to the transistor "length" (minimum dimension) in order to get back analog performance parameters. Third, newer processes have to run at really small power supply voltages. Old-school metal gate CMOS in 0.5um or larger was good to 18V+--really good for things like guitar pedals. If you have the tools, you'd be better off doing a guitar pedal in a very old technology.

userbinator 5y ago
First, you are very likely "pad limited", the pads to connect the chip to the package are much larger than the actual active chip area. I remember doing the maths for this a while ago, and I believe on a 22nm process you could fit an entire 486 (1.2M transistors) in the area of a single bond pad needed for the later CPUs.
squarefoot 5y ago
> If you have the tools, you'd be better off doing a guitar pedal in a very old technology. The parent poster probably refers to BBD delay lines such as the MN3007 and similar devices, whose awful fidelity and noise characteristics made them famous and very recognizable in old music, especially from the 70s. Emulating them in digital is doable, but that requires more complex circuitry. If one could fit a BBD delay line and its clock generator, plus a LFO and a few low noise opamps on the same die, it would be possible to create delay based (echo/flanger/phaser/chorus etc.) pedals at extremely low costs.

bin_bash 5y ago

They actually can be worse in the case of space travel. You get outside the atmosphere and the sun can cause a lot of problems with newer chips. https://www.theverge.com/tldr/2021/3/2/22309412/nasa-perseverance-mars-rover-processor-cpu-imac-1998 https://www.theverge.com/tldr/2021/3/2/22309412/nasa-perseve... Of course this isn't a problem most of us will ever deal with but I still think it's interesting.

marcan_42 5y ago

You literally can't do it. The smaller the process node, the smaller the voltage you can handle and the more delicate the chip is. At 5nm you can't even make USB transceivers; Apple M1 machines had to use external level converters for all the USB ports for this reason.

hristov 5y ago

The thing about power chips is that smaller feature size is not necessarily a good thing. With logic chips, you are essentially moving data and doing math. And you have electrons here and there representing data. It does not matter how many electrons represent a particular bit of data, as long as they can do it reliably. If you can get your feature sizes smaller and have one hundredth of the electrons represent the same bit -- good for you. As long as the data is correctly stored and the math is correct , the fewer electrons the better. Similarly it does not matter what voltage these electrons are kept at. As long as you can tell ones from zeros and can do the math correctly, the lower voltage, lower power and lower heat dissipated - the better. It is different with power electronics. There often you have to provide a certain amount of power to actually move something, or make a motor turn, or make a speaker make sound, etc. So the amount of current and/or voltage your chips produce will actually matter. Say you have a guitar amp. What if someone told you that at a great cost, they could make the chips at that amp a hundred times smaller. They would of course provide a hundred times less power which would make your speaker a hundred times more quiet (well, 2 db, but you get the idea). Would that be a good deal? Not really. That is why analog and power firms like ON Semi (mentioned in the article) tend to look for old equipment. They do not need everything this small. Many of their chips actually require larger features because they have to move a lot of current and/or handle high voltages. But that does not mean that their chips are old technology. Not all innovation is making things smaller. There is plenty of innovation going at the larger sizes.