Mass downloading datasheets from Digikey - Page 1
Forum section: electronics / projects

author: bairdbankovic
author_rank: Newbie
timestamp: December 25, 2024, 11:34:42 pm
content: Hi all! I am trying to build an amplifier that works from room temperature (ideally) to ~10K. Si based devices will freezout at about 40K, but many will fail well before that. Devices made of GaAs or Ge may perform better at lower temperatures, and so I am looking for transistors (even better, op amps) that are made of GaAs or Ge substrates.Unfortunately, this is not a common search term, but I find that some datasheets say what substrate material the device uses. What I would like to do is download a bunch of datasheets (say for all transistors on digikey) and search for "GaAs" or "Ge", and look at the devices that show that text string in their datasheets.Does anyone know how to mass download datasheets from Digikey? -- Or know a database that does allow you to download many datasheets without needed to download each individually?I know that device performance will be very different at room temperature than at 10K, I am happy to buy a number of devices and test for the best one to use. My goal is to make an amplifier as good (low temp, and linearity) as possible, but if it cannot work at 10K, I would like to try to get it working as low as possible. I cannot heat the device due to a lack of cooling power on the refrigerator.Thanks for the help! Baird

author: moffy
author_rank: Super Contributor
timestamp: December 26, 2024, 05:17:47 am
content: Perhaps you have seen this article:https://pmc.ncbi.nlm.nih.gov/articles/PMC7271645/It looks like BJTs are ineffective at cryo temperatures due to falling Beta with temperature, so if you want an amplifier probably CMOS based would be best as the basic MOSFETs still function, with caveats, at low temperatures.

author: bairdbankovic
author_rank: Newbie
timestamp: December 28, 2024, 04:19:39 am
content: Hi Moffy, I have seen this paper before, but thanks for linking it. For much of last year, I was working on building a precision transimpedance amplifier that would work in a cryostat at 77K. I ended up using an OPA828, but I think the device is made of Si (never cracked it open and did xray diffraction) - and it was able to work at that temperature because the die was heating up.I found a solution for the mass-downloading. I ended up writing a python program to click download buttons and then next page button, downloading each datasheet manually. Took about 2 days to complete, but now I have 30,000 datasheets on my hard disk!Cheers - Baird

author: moffy
author_rank: Super Contributor
timestamp: December 28, 2024, 05:31:47 am
content: There are all CMOS opamps e.g. Digikey:https://www.digikey.com.au/en/products/filter/linear/amplifiers/instrumentation-op-amps-buffer-amps/687?s=N4IgjCBcpgbB0QGMoDMCGAbAzgUwDQgD2UA2iAMwVgCsAHAOwiEAsdLATLLMyG57Cat2HBgAZe-LnRABdQgAcALlBABlJQCcAlgDsA5iAC%2BhALQcooFJC0BXAsTIgackyFMBOS8ih2HJSHIIWSNQoAThey might require a lower supply voltage but should work at the lower temp as long as their internal biasing circuitry works.

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2024, 10:45:31 am
content: See also:https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/219106/op-amps-at-very-low-temperatures

author: Terry Bites
author_rank: Super Contributor
timestamp: December 28, 2024, 12:07:13 pm
content: You might (will) piss off Digikey if they see what you're doing. Don't advertise what you're up to. No names!Still.Use a WebCrawler,https://datadome.co/bot-management-protection/crawlers-list/

author: tooki
author_rank: Super Contributor
timestamp: December 28, 2024, 12:41:18 pm
content: Quote from: Terry Bites on December 28, 2024, 12:07:13 pmSince Digikey's primary datasheet links are direct links to the manufacturer websites, Digikey won't even notice.Digikey does have backed-up, self-hosted copies of most datasheets, but they are not what is linked on the lists of products. You have to go into the product page, open the "HTML datasheet" link, and then there's a link to download the PDF.

author: Terry Bites
author_rank: Super Contributor
timestamp: December 28, 2024, 02:49:16 pm
content: I suppose why the question is, why the hell you would do this. It's very suspect.Are you running one of those "all" data sheet clickbate BS sites?I'll ask Digikey if they think its ok..... I'm sure it is.

author: Shock
author_rank: Super Contributor
timestamp: December 28, 2024, 03:29:31 pm
content: Quote from: Terry Bites on December 28, 2024, 02:49:16 pmMind if I download some transistor datasheets to find the exact ones I need Digikey? No? Ok thanks.

author: David Hess
author_rank: Super Contributor
timestamp: December 28, 2024, 11:01:15 pm
content: I have used silicon bipolar transistors, bipolar integrated operational amplifiers, bipolar integrated regulators, power MOSFETs, and zener diodes down down to 77K without problems. Obviously 10K will be different, but 77K is cryogenic according to that article and it says these will fail. I suggest running your own tests to qualify parts.

author: SiliconWizard
author_rank: Super Contributor
timestamp: December 29, 2024, 12:44:31 am
content: You may hope for much better search in those websites instead. That's where "AI" could actually be useful, and that wouldn't require downloading hundreds of datasheets. I don't know if that will happen.At the moment, I'm under the impression that AI is being used everywhere except where it's actually useful. Oh well.

author: moffy
author_rank: Super Contributor
timestamp: December 29, 2024, 01:45:19 am
content: Quote from: SiliconWizard on December 29, 2024, 12:44:31 amI asked ChatGPT to recommend some 2Ms/s parallel output 16bit ADCs, and while it gave one or two reasonable suggestions it also gave quite a number of nonsense answers, quite useless for even such a simple question I really thought it would do better.

author: peter-h
author_rank: Super Contributor
timestamp: December 29, 2024, 08:43:26 pm
content: The standard way to scrape websites is to insert pauses. Make them random, up to a few seconds. It slows down the grab but usually not a problemIf you get problems, play around with browser agent strings and vary these.A site can block bot activity by running the hidden google recaptcha, which is very easy...ChatGPT is just a piece of software doing statistical analysis on a lot of text. There is no "AI" in itAI basically doesn't exist.

author: bairdbankovic
author_rank: Newbie
timestamp: December 30, 2024, 11:19:41 pm
content: Hi all,Thanks for the comments, using my auto-clicker seems to be working (but keep it on the hush hush please). It seems to be downloading things from the manufacturer's servers, I don't think Digikey stores most of the datasheets on their servers.As for part qualification, I absolutely expect to have to test my own parts. This is potentially for use on LHe4 cryostats -- viz. scanning tunneling microscopes. The heat loading is very important, and that is something I would need extensive testing to get right. I'll post back with some results in case yall are curious.At the moment, I am looking at op amps - which I tested about 50 least year in a cryostat for such a project. I am curious if non-sillicon op amps are really a thing. Especially GaAs!Cheers - B

author: wilfred
author_rank: Super Contributor
timestamp: December 31, 2024, 01:11:50 am
content: Quote from: Shock on December 28, 2024, 03:29:31 pmIsn't that why they provide the datasheets so you can download them? I don't see the benefit of mass downloading them if you still have to read them. Now if you could use AI to filter them then that would be a great use of AI. Regardless of whether you think it is not actual intelligence. It would save time.

author: Shock
author_rank: Super Contributor
timestamp: December 31, 2024, 05:53:03 am
content: I know I've made some very poor decisions recently, but I can give you my complete assurance that my work will be back to normal. I've still got the greatest enthusiasm and confidence in the mission. And I want to help you.

author: tooki
author_rank: Super Contributor
timestamp: December 31, 2024, 05:46:56 pm
content: Quote from: moffy on December 29, 2024, 01:45:19 amTo be honest I’m surprised people expect it will give good answers. The more technical the question, the worse it performs. And it isn’t a real-time search of the web, either. The data it does have is months to years old.

author: rfdave#gmail.com
author_rank: Contributor
timestamp: January 01, 2025, 02:55:00 am
content: There are amplifiers that are designed to work down at those temperatures, have you looked at what's commercially available?These folks have some parts -https://www.amplitechgroup.com/[