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Frozen Chip from IBM hits 500 GHz
sideshow2004 writes "EETimes is reporting this morning that IBM and Georiga Tech have demonstrated a 500 GHz Silicon-germanium (SiGe) chip, operating at 4.5 Kelvins. The 'frozen chip' was fabricated by IBM on 200mm wafers, and, at room temperature, the circuits operated at approximately 350 GHz."
I think that speaks for itself.
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Arggg read the article they said they wanted to test the theoretical limits of these chips. They know speed increases with temperature. They wanted to know how much.
Ooo man the floppy drive is broken. No wait. The computer is just upside down.
That's a pretty odd microwave then, since most of them operate at 2.45 GHz, which is chosen because of the way it causes liquid water molecules to vibrate. See this article, particularly the graphs showing dielectric temperature as a function of frequency. It's pretty clear that a 10GHz microwave oven would be a lot less efficient at heating water than a conventional 2.45 GHz one, although I suppose you could choose a multiple of 2.45GHz and probably still have a functional product.
Overall, unless your goal was to build a miniature microwave (a 21st century E-Z Bake Oven?), I don't know why you'd want to use 10GHz instead of 2.4Ghz ones. The tolerances of parts in the magnetron and waveguide would have to be much tighter, I think, and this would almost certainly cause it to be more expensive.
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Didn't you ever think that if you had a digital signal entering your cell phone at 2.4 Ghz, you'd need a transistor in there that could switch at least that fast? You realize that there are other types of chips than microprocessors, right?
Not really, because an EE would know that it's not just the RF output on a cellphone that works at 2.4 GHz, but also the signal processing unit. There is a digital system in the phone that natively controls the signal, rather than using older analog techniques. The general-purpose CPU for playing crappy java games and displaying inane text messages from your friends runs at something much lower than that, of course.
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I just wanted to point that out, I think some posters are thinking about it incorrectly: "The 500 GHz mark was the goal when Feng and UI colleagues received a $2.1 million, five-year grant for the project from the Defense Advanced Research Projects Agency in October. In contrast, the transistors inside the central chip of a powerful personal computer run at around 50 or 100 GHz, Feng said. The fastest that such a chip runs as a package is currently around 3 GHz." http://www.news-gazette.com/news/local/2003/01/24/ fastest_transistor_made_at_ui/
In addition, University of Illinois broke 600 Ghz last year.
http://www.physorg.com/news3662.html
"The speeds quoted in this article are maximum rated *switching* speeds of a single transistor. Synchronous logic designs of the type found in microprocessors involve synchronous cells (known as flip-flops) and asynchronous gates providing boolean functions on the signals passing between flip-flops. The maximum rated frequency of any design is limited by the slowest path between flip-flops and this is what the clock signal will be set at.
As the paths between the clocked flip-flops are typically anywhere between 2 and 10 logic cells deep and with each one comprising 10's of transistors (usually in complementary configuration to aid switching speed), the overall figure for an ASIC design such as a uProcessor would be at least 2-4 times slower than the maximum transistor switching speed (it's not quite cumulative, because as one transistor starts switching, the voltage at the at the `gate' of the next one has already started changing causing it to start conducting, and so on). I also have a suspicion that there would be other real-world constraints such as cross-talk (noise between transistors) and thermal problems. I'd hazard a guess that a production-quality chip would be somewhere in the region of a tenth the speeds quoted here!
However, these new materials and structures still make for an impressive speed gain over traditional Silicon CMOS designs." (The speeds quoted in this article are maximum rated *switching* speeds of a single transistor. Synchronous logic designs of the type found in microprocessors involve synchronous cells (known as flip-flops) and asynchronous gates providing boolean functions on the signals passing between flip-flops. The maximum rated frequency of any design is limited by the slowest path between flip-flops and this is what the clock signal will be set at.
As the paths between the clocked flip-flops are typically anywhere between 2 and 10 logic cells deep and with each one comprising 10's of transistors (usually in complementary configuration to aid switching speed), the overall figure for an ASIC design such as a uProcessor would be at least 2-4 times slower than the maximum transistor switching speed (it's not quite cumulative, because as one transistor starts switching, the voltage at the at the `gate' of the next one has already started changing causing it to start conducting, and so on). I also have a suspicion that there would be other real-world constraints such as cross-talk (noise between transistors) and thermal problems. I'd hazard a guess that a production-quality chip would be somewhere in the region of a tenth the speeds quoted here!
However, these new materials and structures still make for an impressive speed gain over traditional Silicon CMOS designs." (http://www.physorg.com/news3662.html)
Not quite... 500 Ghz (500 x 10^9) is a LONG WAY away from even the beginning of Infrared 3 TerraHz (3x10^12), and visible light does not start until about 430 TerraHz (4.3x10^14).
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Actually, an EE would know that the RF output on a cell phone is specifically NOT 2.4 GHz, but is actually 850/900/1300? MHz. See wikipedia for GSM and CDMA (fine, fine, and TDMA) frequencies.
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After all, even 802.11 gear runs at 2.4GHz, that's enough to cook ones private parts after extended use of a laptop.
No, it isn't. 802.11 kit has an RF power output of around 100mW - absolute peanuts compared to your 800W microwave oven. The RF radiation from an 802.11 network isn't enough to cook anything.
What you might be referring to is the thermal output produced by a laptop, which is down to the CPU and hard drive rather than the 802.11 transmitter and that can cook your privates mostly through conduction, not radiation.
http://blog.nexusuk.org