What is the most common (of the larger) SMD sizes for resistors, caps and the like?
The style number is what I'm after.
Larger the better, for me and unsteady hands but don't want something being phased out either.
Thanks.
The sizes are the length and width in hundredths of an inch. The largest common size is probably 1206 (12 hundredths long by 6 hundredths wide or .12 by .06 inch). But there are lots more parts values available in 0805 size. Unless overall size is at a premium, I normally use 0805 instead of smaller sizes, just because the pick and place tolerances are less of a problem. The yield is essentially
100%. They are also lots easier to hand rework than the smaller sizes.Hello Michael,
Besides the 1206 and 0805 that John mentioned there is also MINI-MELF. They are round which can be good and bad. I kind of like them because you can loosen the tweezer grip a wee bit, roll them onto the pads, tack one side and then solder.
Regards, Joerg
0402 or 0603. Don't worry about the tinier ones for a while.
Then use 0805. You'll still be able to buy them, in a fairly full range, but a bit more expensive.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
You forgot the wink ! ;-)
Don't forget to buy some tweezers. And whatever you do, don't sneeze whilst placing them !
Graham
I bought some of those when I was starting SMT prototyping, mainly because they still have the colour bands for value marking.
I hate them! They roll around everywhere and my tweezers wont hold them properly for some reason. I can't read the colours anyway (even with magnification), they look wrong somehow.
I use standard 0805 now, much nicer.
-- John Devereux
Like the other guys, I think 0805 is a good choice. Get some decent lighting and magnification... even 1.75x drugstore reading glasses work pretty well with 0805's. SMD is *not* difficult.
John
It isn't hard if you're using a board. It took me awhile to learn how to do do reliable dead-bug style prototypes with SMTs, but it's possible.
And for hacking around, it's much easier to stand the 0805s up like billboards instead of flat. It looks ugly, but the tweezers never slip, and you can get the iron into the tightest-packed places that way. Prototype SMT boards usually die by having pads cooked off them(*), and the billboard trick speeds up soldering significantly.
Cheers,
Phil Hobbs
(*) Various s.e.d denizens have recommended using one via per pad, to reduce this problem, but I dunno--that's a lotta vias.
Do parts that little have any kind of markings, with any rhyme or reason? Or do you just have to remember which bin you picked it out of?
Never mind, some do, some don't. I got out my 5X illuminated magnifier, ;-) and looked at a dead video adapter that's loaded with little things that look like coarse-ground black pepper, and a couple of them had "103" without the quotes printed on them, so they're probably resistors. They're about 0.08" x 0.05". =:-O lessee - there's a couple caps: Nope, they just looked bigger because they're pinkish beige, rather than black. Ooh! There's a big'un! No markings, but it's about 0.12" x 0.06". Oh, there it is, "L4" is screened next to it. ;-)
Sheesh! Not my cup o' tea, thanks - I guess I'll go the FPGA route and let somebody else solder the stuff down. ;-P
Cheers! Rich
One great thing about SMT is that all my prototyping stock fits into a single small box of envelopes, which goes on the bench in front of me. I have a wall full of plastic drawers for the through hole stuff (which I rarely touch),
-- John Devereux
Hello John,
Once I passed 40 I realized that I needed 3x drugstore glasses for that. Bought them more by accident, tried them on, and "ahhhh". It's also safer to solder with glasses in case an electrolytic decides to put on a pyrotechnic show.
SMD is *not* difficult.
Sometimes I find that it is even easier than thru-hole. No more turning around of the board. But it sure is a drag getting older while all the stuff shrinks to less than 0402.
Regards, Joerg
But you're still just a baby ;-) ... I'm just weeks away from 66 :-(
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
Global Warming is God\'s gift to the Blue States ;-)
I think I'll stick with the larger for resistors, only because I shake like Don Knotts anymore.
Is that the case with most popular cap values as well?
Is 1206 just as available as 0805 in caps?
I did some 0805 today but those 0603 would drive me nuts.
I've just been placing with some scotch tape and tacking one side under an overhead magnifier.
I seem to break the parts a lot if I stand them up. The end caps come off.
These snap-apart boards are slick for small protos and test circuits:
I just snap them apart and attach them here and there to a piece of copperclad with hot-melt glue. Solder on a few SMB connectors and bigger parts, and wire it up.
For anything more serious, lots of people, like AP Circuits, will do a small batch of 2-side plated-thru boards for $60 roughly.
John
Forget capacitors. But all the 0805 resistors I use have the resistor code printed on them (white on black), even the 1% ones. And I am near sighted enough to read them without additional magnification.
Check out 0.1% resistors, for example. And compare the price of typical bypass or C0G capacitors in 1206 vs. 0805. or 0603. OTOH, 0402 tend to come in reels of 10K, which is double that of
I think their stock is biased towards the older parts, compared to Asian production stock, but here's Digikey's stock situation:
Capacitors
size # of different parts
1206 1336 0805 1798 0603 1976 0402 1432 0201 716Resistors
Thick film Thin film
1206 6364 127 0805 6375 1420 0603 5167 1219 0402 2585 268 0201 252 290805 is very comfortable to deal with. I still find 0402 a bit tiny and tend to lose a few in solder blobs or ejected into space from the carrier tape. But okay for a prototype or two-- the last one I did had 75 or so 0402 caps and resistors per board, though I needed a shot of single-malt by the time it was done.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
I'm right in the middle. ;-) I don't normally wear glasses, but have a pair of +1.75s for close work. Anything stronger and I get nauseous. I'm looking for a pair of +1.00 or +1.25s for computer work but the drug and dollar stores never seem to have ones bigger than my displays. I like tiny fonts on large screens. ;-)
-- Keith
Drug and dollar stores? Why don't you go to a proper optometrist and optician (ophthalmologist wouldn't hurt either at your age, he or she will check for glaucoma), lay down a few Franklins, and get some nice purpose-made optical wear. Your eyes will thank you.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Pure brute force, tsk tsk. Of course, for someone who puts 48V forward bias on a diode, what can one expect? ;)
Those are cute, thanks. I'll have to order some. But once I have the SMTs on there, I'll have to restrain myself from attaching them to the board upside-down with Krazy Glue.
Yah, I know I can get that done...but I have way too many rocks to push to do my own PCB designs too, alas.
Cheers,
Phil HObbs
I knew I should have been a lumberjack.
Tsk tsk. It's sad what years of sniffing Krazy Glue can do to a fine mind.
John
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