Atmel Mega chips, normal versus automotive - Page 1
Forum section: electronics / general

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 07:40:54 am
content: Having found that the parts digikey were listing were not on the datasheet as i was specifically after 125C grade I phoned them and spoke to a very helpful chap who pointed out that there is a "parallel" automotive range with a separate datasheet.So, are the two series the same but for temperature range and ruggedness ? Atmel seem to have left plenty of room for trouble with people scratching around trying to work out what it what in the dual Atmel universe.

author: Kremmen
author_rank: Super Contributor
timestamp: July 22, 2014, 08:50:46 am
content: Quote from: Simon on July 22, 2014, 07:40:54 amWhy not check what Atmel has to say about their own products?http://www.atmel.com/products/automotive/automotive_microcontrollers/default.aspx

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 08:52:25 am
content: you just proved my point, a separate section on what most would think is the same parts. If there are just a tougher but same fit and function variant they should be on the same datasheet or at least a mention, if they are that different they should have different part numbers

author: Precipice
author_rank: Frequent Contributor
timestamp: July 22, 2014, 10:15:47 am
content: Manufacturers really don't care at all about low volume purchases of their automotive parts. They're not going to go to any effort to support you, you're just a pain and a loss now and in the future. They want volume, they want forward orders and they want someone to whom the papertrail aspect of automotive qualification has some meaning.(If you want some serious temperature range and purchasing nightmares, have you met TI's HT stuff?http://www.ti.com/product/sm470r1b1m-ht-55oC - +220oC, enjoy your weird PCB substrates, your high melting point solder, and your £274.45 from digikey...Ooh, there's an MSP430, and it's even available through distribution...http://www.ti.com/product/MSP430F2619S-HT- ah, but that's only rated from -55 to +150. )

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 10:23:31 am
content: Yes I'm aware that TI do pretty well rated stuff and they are like rocking horse shit.The atmel automotive variant is a lot more expensive and I'm sure that plenty get bought and they are not a loss maker

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 10:28:31 am
content: http://www.atmel.com/devices/ATMEGA168AUTOMOTIVE.aspx?tab=overview150C ? no mention of that on the datasheet they link to.........

author: Kremmen
author_rank: Super Contributor
timestamp: July 22, 2014, 10:31:41 am
content: Quote from: Simon on July 22, 2014, 10:28:31 amJeez - a bit of effort please:http://www.atmel.com/Images/Atmel-7781_Automotive-Microcontrollers-ATmega16-32-64-Appendix-A_Datasheet.pdf. How hard can it be? Only the 1st document on the automotive parts page...

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 11:32:22 am
content: yep, so 3 datasheets to cover one part, well 2 once you realize your in a "parallel universe"

author: Precipice
author_rank: Frequent Contributor
timestamp: July 22, 2014, 11:42:41 am
content: Yes. You're stepping outside the spoonfeeding zone. Slow down, read everything, read the errata, read everything again. Then design exceedingly carefully, and don't be particularly surprised if silicon availability means you can't actually build it.Here be dragons. Enjoy!

author: nctnico
author_rank: Super Contributor
timestamp: July 22, 2014, 02:46:42 pm
content: Especially when dealing with Atmel: READ the fine print, then read the finer print, then read between the lines and then test the sh*t out of a null-series to be sure a circuit actually does what it is supposed to do. I'd be more comfortable with using something automotive rated from an A-brand like TI, NXP, Analog devices.

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2014, 03:57:39 pm
content: Quote from: Simon on July 22, 2014, 07:40:54 amOften the silicon is the same but the wider temperature range parts take more testing time, meet a lower performance standard, and use a more expensive package even if it is the same form factor. A separate datasheet may be produced just to avoid confusion since most customers will be using the commercial parts.

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 04:45:15 pm
content: If they are that different the part number could be changed

author: David Hess
author_rank: Super Contributor
timestamp: July 22, 2014, 05:05:41 pm
content: Quote from: Simon on July 22, 2014, 04:45:15 pmSometimes they do change the part number like with the 74 versus 54 series of TTL logic but then combine the datasheets anyway.Another good example is the ubiquitous 124, 224, and 324 (and 2902!) quad operational amplifiers. For parts that used this numbering scheme, the first digit indicates the service and temperature range with 1 being military, 2 being industrial, and 3 being commercial. I think the 2902 is "consumer" grade. Usually they are all included in the same datasheet but not always.

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 05:26:57 pm
content: I don't have a problem if it's simply a temperature difference, but atmel can't seem to make their minds up, the automotive series aren't mentioned on the main parts datasheet, then you find there is a parallel datasheet with a large additional sheet for yet a more extended range, it makes it hard to compare things or know if you can trust that certain features are the same, it's a mess.

author: Precipice
author_rank: Frequent Contributor
timestamp: July 22, 2014, 07:13:00 pm
content: There's no crossover (that Atmel care about) between the two parts. Either you want the automotive, in which case you fetch the automotive dataset, or you don't, in which case you fetch the standard stuff.You've argued yourself into a middle ground that doesn't really exist, and (I imagine) your volumes are nowhere near enough to make them care.Silicon vendors, like any sane entity, want maximum return from minimum effort. A stream of support-intensive, zero volume customers, is pretty much the exact opposite... If it feels like you're swimming against the flow, here, it's because you are. It'll be hard work, and only you can decide whether it's worth the effort. Somebody had better be paying you for this time, one way or another.

author: Simon
author_rank: Unknown
timestamp: July 22, 2014, 07:16:26 pm
content: It's just that I never knew there was another range until I found them through digikey, Atmel don't seem to be "cross selling" I could have gone elsewhere had I not found the automotive parts. What I'm saying is if the registers etcv are all the same why even bother with 2 datasheets, jut do seperate sections for the stuff that matters, it just looks like more work for atmel who don't seem to be keeping on top of updating duplicate material. Last promotional video i saw of atmel they were banging on about their automotive presence.

author: SirNick
author_rank: Frequent Contributor
timestamp: July 22, 2014, 08:51:00 pm
content: I suspect that if youneedautomotive-grade parts, you know where to look to find them. High-reliability stuff and/or designing for extreme environments probably tend to not be an engineer's first gig. How many one-off vehicle ECUs get made? At that level, there's likely to be a more direct relationship between parts vendor and product engineer than "what can I find on Digikey?"

author: zapta
author_rank: Super Contributor
timestamp: July 22, 2014, 09:41:56 pm
content: Quote from: Simon on July 22, 2014, 07:16:26 pmIt may reflect internal organization. Two divisions, each wants to control its own destiny.Frustration understood. Luckily we have Digikey.

author: Stonent
author_rank: Super Contributor
timestamp: July 22, 2014, 11:32:09 pm
content: When you enter automotive territory you're then subject to a lot of regulations that wouldn't exist in a battery powered consumer device.In that case, the parts may have numerous safety certifications and that may cost more. A cost that they'd rather not hand down to the people who don't need it. In the case of intrinsic safety as Mike said in one of his videos, something along the lines of, it's not a matter of knowing it is safe, it's a matter of showing that you've made every attempt from all different angles to even prevent the unknowns from happening.Similarly the 54 series logic vs the 74 series logic. Same basic device but the 54 series is rated to military specifications. For some ranges ceramic is preferred over plastic.