Semtech IC -- any good? - Page 1
Forum section: electronics / projects

author: blueskull
author_rank: Unknown
timestamp: October 03, 2017, 07:42:28 am
content: I just came across a very particular need -- a 3.3V LDO with open drain reset output within 2mm*2mm package and be <$2.After extensive search, it seems I can only find 2 candidates, one being Micrel MIC5332, the other being Semtech SC560.It seems like SC670 is better in all aspects for my needs, but I want to know if Semtech is a reliable brand in terms of long term availability.I'm not talking 10 years or 20 years. 3~5 years is good to me, but I need to make sure it's constantly available on DK/Mouser.Any ideas about this brand?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 03, 2017, 08:15:51 am
content: MIC5332 (I've used this before IIRC) and SC560 are marked as "active". Don't see SC670 (typo..?).5 years very likely.Tim

author: amyk
author_rank: Super Contributor
timestamp: October 03, 2017, 09:15:41 am
content: Neither of them are new companies, so you probably shouldn't worry about them disappearing anytime soon...Semtech has been around since 1960.Micrel since 1978 but Microchip has bought them.

author: daveshah
author_rank: Unknown
timestamp: October 03, 2017, 03:03:16 pm
content: I know Semtech are rather well known for their LoRa wireless parts, which I've had success with in the past. Didn't know they did things like LDOs as well though.

author: lukier
author_rank: Unknown
timestamp: October 03, 2017, 03:19:25 pm
content: Quote from: amyk on October 03, 2017, 09:15:41 amCompanies not, but their parts do.My LeCroy WaveRunner 6100A uses Semtech USB to Resisitve Touch Screen IC - UR7HCTS2-USB. Try finding anything about this chip on their website, not to mention the drivers (non-existent, except trial version from TouchBase).I had to remove this chip and I rewired AR1100 from Microchip, no problems with the drivers now.Based on that experience I wouldn't touch Samtech parts with a stick.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 05, 2017, 04:18:16 pm
content: IME,allmanufacturers do this shit every now and then. Even the "best" and most trusted ones (availability-wise), such as TI, so it's meaningless to start avoiding one because of a single case of poorly handled obsolescence - you just get hurt again and again every now and then, and finally have no one you can trust.... which is the truth in the component business: trust no one.I have stopped worrying whether it's TI or some never-heard small IC company. Both will fuck you up randomly. Sometimes, you can actually talk with the small ones, while the big ones won't even listen if you are a small customer. I look for: short manufacturer standard lead time, active status, thousands in stock on multiple suppliers. Combination of direct manufacturer sales & stocking on multiple suppliers is a good sign. But still, you never know.OTOH, when someone does this shit too much, collective experience builds up: just like everybody knows to avoid Maxim.In any case, for a small customer (say, < 10 million USD sales per year), everything is horrible, up to extensive research, and finally, pure luck.Designing in multiple footprints & modding capabilities helps, but it often compromises design performance & increases design cost.

author: lukier
author_rank: Unknown
timestamp: October 05, 2017, 04:34:54 pm
content: Quote from: Siwastaja on October 05, 2017, 04:18:16 pmI agree in general. Just in Semtech's case I knew the part is long obsolete, I didn't want parts from them, I didn't want the application engineer support etc, just some basic info, datasheet and the last available driver. Probably in total much less than 1 MB for them to host on their website. They cannot even afford that.Compare that with LT, for example, LT1088 is probably obsolete for the last two decades, but LT still admits it was their part, provide basic info, datasheet and app notes:http://www.linear.com/product/LT1088

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 05, 2017, 05:16:04 pm
content: When I said the parts show "active", I should add: I looked them up on an inventory analysis tool.I think there were more than a half dozen distributors showing stock, and no flags for life cycle change or lead time.Tim

author: free_electron
author_rank: Super Contributor
timestamp: October 05, 2017, 05:48:41 pm
content: Quote from: blueskull on October 03, 2017, 09:18:36 am

author: Siwastaja
author_rank: Super Contributor
timestamp: October 05, 2017, 06:44:24 pm
content: Quote from: lukier on October 05, 2017, 04:34:54 pmOh, this sounds similar to what I noticed from TI just some time ago. Luckily, at that point, I was onlyconsideringtheir (expensive) chip, not committed yet. They actively denied supplying the full datasheet for the chip, only providing a "stub" datasheet, while not giving out clear licencing terms, only some vague "maybes", and very little data. This was compounded with the act of denying the existence of other (older) products in the same segment, just a few years old, with no discontinuation notice to be found anywhere, just product pages and datasheets vanished from their servers as if they never existed - some externally hosted datasheet copies elsewhere provided more insight. I guess they fucked up some customers with that. Without clear licencing terms, or even meta info (info about how to get the info), this is a nightmare - which is one of the reasons I looked elsewhere, and found a better product.But this experience doesn't mean that I would never use TI parts again - that would be extremely stupid, since, in general, TI parts have good chances of being available, and TIusuallyhandles discontinuation & product data cases well - they are one of the best, actually, I guess.T3sl4co1l:I've been thinking about building an inventory analysis tool for a long time - didn't know they existed. Any suggestions? What are you using?Something like automatically fetching the full inventories of several distributors once a week, for example, to draw stock availablity graphs over time, etc.

author: lukier
author_rank: Unknown
timestamp: October 05, 2017, 07:06:20 pm
content: Quote from: Siwastaja on October 05, 2017, 06:44:24 pmTI might be a bit peculiar in this context, as they make some parts that are unknown to the general public at all, or with the stub datasheet and will need NDA for more info. The reason is that TI often makes chips (often customize some existing design) for big customers that need some extra functionality or a chip for some special fixed function. Sometimes some of these parts trickle down and are released to the general public.Case in point: TMS320TC16488 DSP, good luck finding thatAll that might make some parts have messy documentation, status going from public to private or under NDA and so on. I guess it is similar if you would ask LT about LT-FLU chip datasheet.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 05, 2017, 11:09:34 pm
content: Quote from: Siwastaja on October 05, 2017, 06:44:24 pmYou can probably access distributor APIs for that. Of course, you'll have to integrate each one, or go through an aggregator like Octopart.I have access to Siliconexpert through a perennial client. It's nice for checking things out.Don't know what it costs them, but I imagine it's something you wouldn't bother with unless you're moving lots of product...Tim

author: marshallh
author_rank: Unknown
timestamp: October 05, 2017, 11:33:54 pm
content: I'm happy with the Semtech buck regs I've used so far, very good price/performance. They do evolve faster than the dinosaurs like LTC.

author: senso
author_rank: Frequent Contributor
timestamp: October 06, 2017, 01:53:17 am
content: Quote from: lukier on October 05, 2017, 07:06:20 pmLots of laptop specific charger IC's and BMS, yay for not even Aliexpress having those.I really want to remove 5 chips from various dead laptops to get one with a working charging circuit.What is nice is random TI pages having the part number somewhere, open them, please loging with special account and sign phonebook of NDA's to even smell the color of those pdf's.