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#31
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Temperature Range of modem?
1Adata wrote:
yes, but this does not mean that electronic components do not depend on temperature; an overheating makes very strong impact on electronic chips. --------- Sure, I agree with that. One metric I would suggest to you, is whether the equipment function stopped due to the temperature. The processor inside the box should "crash", once it gets past a certain temperature. Going an additional number of degrees past that point, could lead to physical damage. If the equipment operated throughout the overheated interval, I would argue that is a crude metric that critical temperatures were not exceeded. Some temperatures 1) Silicon damage (info from our fab many many years ago) = 135C The full 135C can be survived if the chip is housed in a ceramic package. They no longer use ceramic for most applications. The chip packaging material is now "organic", and may be limited to 90C to 100C, as the packaging material degrades at higher temperatures. So the chip itself can stand 135C, while the packaging is more susceptible. This was the value from our fab. YMMV :-) 2) Simulation temperature (operation not guaranteed correct) = 105C A chip designer tries to prove correct operation at this temperature. Whatever the value is (105C-110C), this would be considered an upper limit during design. 3) Processor may crash (only rough figure) = 70C to 90C perhaps Anecdotal values seen on various processor families. I suppose, it would be possible for a hardware design, to continue to run error free, at the same time as the organic packaging is being degraded. But it is more likely, you'd see some functional degradation before that happens. If the box continued to run, without observable performance degradation, I would argue it is just fine. If it crashed, then it may have overheated significantly. When a device is convection cooled, and you seal the top vent, it would be easy for temperatures to shoot way up. The value of cooling effectiveness of convection is not that great. Having to fall back to conduction cooling, because the vent is blocked, is not going to work very well if the product has plastic packaging. It might behave marginally better if the casing was metal. There have been cases of small devices like this in the past, where the internal temperatures were really too high for long life. Some people had first generation gigabit routers die, because the designers didn't do enough to cool them. So there are products, where the silicon inside is tortured. Some people added ventilation to their own products (voiding the warranty), and their products survived. So not all hardware designers are kind to the silicon. Some chip types *love* to run hot. Back when ECL logic was popular, you could get skin burns from touching the tops of some of the chips. And the chips worked best, when they were that hot. CMOS has different behavior, and gets slower at high temperatures. Paul |
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#32
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Temperature Range of modem?
1Adata wrote:
yes, but this does not mean that electronic components do not depend on temperature; an overheating makes very strong impact on electronic chips. --------- Sure, I agree with that. One metric I would suggest to you, is whether the equipment function stopped due to the temperature. The processor inside the box should "crash", once it gets past a certain temperature. Going an additional number of degrees past that point, could lead to physical damage. If the equipment operated throughout the overheated interval, I would argue that is a crude metric that critical temperatures were not exceeded. Some temperatures 1) Silicon damage (info from our fab many many years ago) = 135C The full 135C can be survived if the chip is housed in a ceramic package. They no longer use ceramic for most applications. The chip packaging material is now "organic", and may be limited to 90C to 100C, as the packaging material degrades at higher temperatures. So the chip itself can stand 135C, while the packaging is more susceptible. This was the value from our fab. YMMV :-) 2) Simulation temperature (operation not guaranteed correct) = 105C A chip designer tries to prove correct operation at this temperature. Whatever the value is (105C-110C), this would be considered an upper limit during design. 3) Processor may crash (only rough figure) = 70C to 90C perhaps Anecdotal values seen on various processor families. I suppose, it would be possible for a hardware design, to continue to run error free, at the same time as the organic packaging is being degraded. But it is more likely, you'd see some functional degradation before that happens. If the box continued to run, without observable performance degradation, I would argue it is just fine. If it crashed, then it may have overheated significantly. When a device is convection cooled, and you seal the top vent, it would be easy for temperatures to shoot way up. The value of cooling effectiveness of convection is not that great. Having to fall back to conduction cooling, because the vent is blocked, is not going to work very well if the product has plastic packaging. It might behave marginally better if the casing was metal. There have been cases of small devices like this in the past, where the internal temperatures were really too high for long life. Some people had first generation gigabit routers die, because the designers didn't do enough to cool them. So there are products, where the silicon inside is tortured. Some people added ventilation to their own products (voiding the warranty), and their products survived. So not all hardware designers are kind to the silicon. Some chip types *love* to run hot. Back when ECL logic was popular, you could get skin burns from touching the tops of some of the chips. And the chips worked best, when they were that hot. CMOS has different behavior, and gets slower at high temperatures. Paul |
#33
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Temperature Range of modem?
"Mr. Smith" wrote in message ... On Wed, 15 Jul 2009 15:12:29 +0300, "1Adata" wrote: does anyone know, what is Temperature Range for the Cisco EPC3000 Cable Modem: Max and Min temperature? Is it still safe when modem worked near 11 hours with partially blocked top ventilation openings? On the top surface of Cable modem has been placed VoIP adapter, which partially blocked the top ventilation openings, plus there where strong heat emitted from this adapter itself. As a result, both the Cable Modem and adapter strongly heated. Is it still safe for Cable Modem? Good lord, why are you asking this here? What does this have to do with XP? You did notice the letters X and P before the workd hardware in the group title, right? Indeed. Ask in a *hardware* newsgroup. Only a 13 year old mentally retarded ****wit would consider that this is the wrong newsgroup. Ignore him like everyone else does. |
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