Ebay mini rant.. - Page 1
Forum section: electronics / general

author: cloudscapes
author_rank: Regular Contributor
timestamp: November 12, 2012, 04:12:24 am
content: So a number of sellers are offering the H7665 570ksps 16bit ADC at a really good price (for those specs), example:http://www.ebay.ca/itm/HARRIS-SOP-8-16-Bit-570-kSPS-CMOS-ADC-H7665-/261112273696?pt=LH_DefaultDomain_0&hash=item3ccb811b20And none of them... NONE of them have any datasheet or even a pinout. already asked a few of them, they answered that I should try google (already did) or a site like alldatasheet.com (already tried). Had they searched on those sites themselves, they'd see that there is zero info (findchips.com too). checked various chinese sites too. a few of them list the chip, but with "no datasheet available" or something. I'm floored! How do they expect people to actually be able to use what they're selling if there is zero info on the internet?if I at least had the pinout, I could probably get it up and running, assuming there are no command bits.Even that much info.wondering if they're fake relabeled chips.

author: johnboxall
author_rank: Unknown
timestamp: November 12, 2012, 04:47:16 am
content: Quote from: cloudscapes on November 12, 2012, 04:12:24 amwell it's eBay ... and look at their feedback - looks like lots of DOAs and pulls. If it's too good to be true it usually is.

author: poptones
author_rank: Frequent Contributor
timestamp: November 12, 2012, 06:22:10 am
content: Ummm.. if you want data on a Harris chip why not contact Harris? They may not seem friendly to experimenters, but they are.

author: free_electron
author_rank: Super Contributor
timestamp: November 12, 2012, 08:19:18 am
content: Harris semi was borged years ago by intersil.The 7665 is a voltage detector. NOT and adc. Harris never made serial adc's...Harris partnumbers did not begin with an H and the logo on that chip is NOT harris logo ( rounded square with hollowed out letter h )Whatever wingpangpong is selling is NOT harris material ( harris semi ceased to exist in the early 90's so the datecode on those chips is wrong to begin with .. )I have no clue what those things are. They could be 7665 s the voltage comparator 7665 that is. Icl7665. One thing is certain : this aint what they label it as...Now, as far as buying this on ebay in china. You have to be bonkers. Go to mouser or digikey

author: amyk
author_rank: Super Contributor
timestamp: November 12, 2012, 11:00:50 am
content: I'm pretty sure they're selling this:http://www.intersil.com/data/fn/fn3182.pdfThe ADC you're looking for is this:http://www.analog.com/static/imported-files/data_sheets/AD7665.pdfwhich is in a completely different package.Possible explanation: someone noticed that a cheap comparator shares almost the same part number as an expensive ADC and decided to sell it as such.

author: cloudscapes
author_rank: Regular Contributor
timestamp: November 12, 2012, 02:06:14 pm
content: Thanks for the info guys. I've already been looking at a few similar parts on mouser and digikey, but for the same specs (pretending for a moment the ebay chip was the real deal) they're almost 10x more expensive, which is why I checked on ebay.I'd expect the occasional seller mis-describing or mis-labeling a part, but the thing is that there are dozens of sellers, all claiming this to be an ADC.Quote from: free_electron on November 12, 2012, 08:19:18 amBecause you never know!Example: I've found some lovely little SOIC8 16-bit DACs for 50 cents a pop on ebay, the PT8211, and they can't really be found in any of the big stores (except futurlec, which I tend to avoid). They work, been using them for years, so I hoped I'd be just as lucky for ADCs.The difference is of course that info on the 8211 CAN be found.

author: T4P
author_rank: Super Contributor
timestamp: November 12, 2012, 08:20:51 pm
content: Of course you won't find a PT part at the big ones, the big ones have never had a Princeton part beforeI only ever heard of their chips, once. The PT2399 that is and that LONG dead, in terms of usage (Only guitar pedals probably i guess but i still see them used in "If it ain't broke why fix it?" karaoke amps)But in any case you can get the DACs and try them out, i know PTC (the company) is not a "wunhunglo"

author: poptones
author_rank: Frequent Contributor
timestamp: November 12, 2012, 08:27:54 pm
content: I'm curious why you avoid futurelec? They're slow as christmas, but they have a nice lineup and good prices. I recently ordered some obsolete radio ICs from there which sell on ebay for a couple bucks each, they have them for like 50 cents. I think I got 25 for about 12 bucks shipped...

author: cloudscapes
author_rank: Regular Contributor
timestamp: November 13, 2012, 12:28:56 am
content: Quote from: poptones on November 12, 2012, 08:27:54 pmOut of 5 orders, 2 of them never made it, and the rest were slower than ebay could ever hope to be, even with ebay's own faults. Probably bad luck, sure, but it sticks with you.I still consider them a good choice for many of those who are not in a hurry and looking for cheap parts.

author: cloudscapes
author_rank: Regular Contributor
timestamp: November 13, 2012, 12:31:59 am
content: Quote from: T4P on November 12, 2012, 08:20:51 pmI agree, and I've used (and still use) the 2399 before I knew about the DAC.It's just that I found that particular DAC thru random ebay searches, just like I found this fake ADC. And I didn't necessarily know about the rest of PT's catalog either, so I figured ebay is (very occasionally) good for finding decent parts that would be hard to find otherwise.

author: poptones
author_rank: Frequent Contributor
timestamp: November 13, 2012, 01:00:18 am
content: PT2399's aint dead, they're used in pedals for sure. In fact, they're pretty popular. I include one in every one of my parts kits.

author: cloudscapes
author_rank: Regular Contributor
timestamp: November 13, 2012, 01:46:16 am
content: Quote from: poptones on November 13, 2012, 01:00:18 amyou build pedals or pedal kits?so do I !

author: Harvs
author_rank: Super Contributor
timestamp: November 13, 2012, 03:07:41 am
content: Quote from: cloudscapes on November 13, 2012, 12:28:56 amI had a bag of MOSFETs from them, all fakes with their breakdown voltage about 1/5th of the real part. On the same order I got a 100 odd electro caps, I had never seen anything made so awfully before in my life.I don't really find them much cheaper than Digikey (as long as you get above the free postage threshold...)