[HN Gopher] Can Electronics made of COTS components work at cryo...
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Can Electronics made of COTS components work at cryogenic
temperatures? (2020)
Author : agarttha
Score : 28 points
Date : 2021-05-29 13:43 UTC (1 days ago)
(HTM) web link (www.onelectrontech.com)
(TXT) w3m dump (www.onelectrontech.com)
| weinzierl wrote:
| As a young engineer working in aerospace I found it both
| surprising and remarkable that the satellites we worked with were
| all designed to operate at and around _room temperature_ [1].
|
| I could understand that you want to avoid temperature changes as
| much as possible to avoid stress on the components. But why
| settle on an arbitrary temperature that is comfortable for
| humans? Of course I learnt quickly that a room temperature design
| makes _a lot_ of things _much_ easier;-)
|
| [1] An interesting tidbit is that in certain fields _room
| temperature_ is used as a technical term to really mean a well
| defined temperature, and that there is a difference between North
| American (25 degC) and the European (20 degC) convention.
| comboy wrote:
| Clueless questions:
|
| 1. Assuming it's easy to keep 20C (I thought it's problematic
| to keep such a low temp for satellite which has problem
| radiating heat away), what about transfer, is electronics not
| yet operating back then or do you use some heating elements
| specifically for bootstrap?
|
| 2. Just to be clear 25C is what is used as room temp in
| electronics and not something you set your thermostat too at
| home, right?
|
| 3. (easily googlable feel free to skip) - how does heat
| management look for satelatie electronics? Are peltiers used?
| Do you just put everything in some heat conductive material? Is
| there some gas sealed around PCB or is it vacuum? In case of
| the latter and if everything is not surrounded by some heat
| conductive substance how do you deal with thermal runaway? Is
| maybe PCB itself and paths enough to make it less bad than I
| imagine?
|
| Thanks a lot, I'm sorry about so many questions, just got
| curious.
| madengr wrote:
| I have designed some satellite microwave PA, and the thermal
| ranges were -20C to +70C, but yes, not even an industrial
| temperature range.
|
| The biggest issue is getting heat out, though my module was on
| a cold plate and I doubt it was ever cycled to those ranges.
|
| The concern was keeping output power and current within spec
| over those ranges; getting enough output power (within
| distortion specs) at hot, and keeping the current under spec at
| cold (so as not to trip a breaker).
| ncmncm wrote:
| Anything works at cryogenic temperatures if you heat it so it
| isn't.
|
| Thus, a big part of the Mars probes', including the Ingenuity
| micro-helicopter's, power budgets is keeping them warm enough
| overnight. The Voyager spaceprobes will be shut down soon not
| because they can't produce enough signal to reach Earth antenna
| arrays, but because they can't keep the equipment warm enough to
| work right.
|
| It would probably be possible to make stuff that would work cold,
| but there aren't enough places to use it to support the whole
| process.
| raziel2701 wrote:
| I'm getting a 404, what does COTS mean?
| ggreer wrote:
| Commercial off the shelf. [1]
|
| 1. https://en.wikipedia.org/wiki/Commercial_off-the-shelf
| a9h74j wrote:
| The link does not resolve for me. I recall discussions and
| assumptions that commercial CMOS could be provisionally expected
| to work to cryogenic temperatures. I have only routinely
| qualified to -40, and many +85C parts for excursions to 105C.
| onelectrontech wrote:
| Author here. Looks like this page got quite a bit of attention--
| and unfortunately our server couldn't handle the load. I'm here
| to answer any questions while you wait for our website to
| respond!
| mordechai9000 wrote:
| Dumb question, since I haven't read the article. What
| constitutes cryogenic temperatures?
|
| I worked for a telecom that deployed a lot of equipment at high
| latitude, in places where temperatures could reach -40 or
| colder. It wasn't my department, but I had the impression that
| we weren't really paying too much attention to the lower end of
| the operating range specified by manufacturers. I recall seeing
| "ice in the feed horn" as a root cause more than once.
| detaro wrote:
| A common definition of cryogenic is "below 120K/-153degC", or
| more general temperatures where "simple" gasses like
| oxygen/nitrogen/... become liquids.
| onelectrontech wrote:
| That sounds reasonable. I didn't have a specific range in
| mind, other than "significantly below the minimum specified
| operating temperature of conventional electronics". The
| article was mostly focused on space applications, so 120K
| seems like a good upper bound for extreme cold in these
| ranges.
| onelectrontech wrote:
| Update: the site should be back up now. Looks like our CMS had
| some issues dealing with the increased traffic. We made a few
| configuration changes so hopefully things will be more stable
| now.
| dvh wrote:
| Is the answer "no"?
| onelectrontech wrote:
| It depends--This doesn't feel like a very satisfying answer,
| but certain devices have been shown to perform better at
| extreme low temperatures (up to a point). However, there is
| the ever-present issue of reliability. For instance, certain
| CMOS devices exhibit improved switching characteristics, but
| the increased hot carrier mobility can cause degraded
| reliability, so certain design trade-offs have to be made.
|
| Of course, many COTS components specify much higher minimum
| operating temperatures in their datasheets, so thoroughly
| characterizing these components is vital for high-reliability
| operation in cryogenic conditions.
| the-dude wrote:
| Service Unavailable
|
| The server is temporarily unable to service your request due to
| maintenance downtime or capacity problems. Please try again
| later.
|
| Additionally, a 503 Service Unavailable error was encountered
| while trying to use an ErrorDocument to handle the request.
| amelius wrote:
| It's not easy to run a website at cryogenic temperatures.
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(page generated 2021-05-30 23:01 UTC)