Post by thread:[EE]: SMD as good as regular components?

I was wondering, are SMD resistors/capacitors just as good as regular sized ones? I'm designing a circuit board and it's a bit tight on space. I'd like to use SMD parts to save space, but not sure if the quality or reliability is up to par. I mean, they are are so damn small! :) Just wanted to make sure. Thanks, Ken -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

I use 0603 SMD resistors on my hobby boards and have never had a problem (apart from my eyesight) Obviously watch current. I've had no trouble with 25mA drives into LED circuits logic control FET transistors. I use the Bulgarian company Olimex for my PCB's, he does a PCB prototype (about 200mm*100mm ish) for $26 plus $5 postage. Outstanding! I can useually get 4->6 PIC circuits out of one card. That's double sided and through hole plating plus all drilling and silkscreen. If you are interested contact.. "Tsvetan Usunov" Email: spam_OUTusunovTakeThisOuTolimex.com Cheers Pete > {Original Message removed}

Ken, Most of the electronics of the day uses SMT components. Things like your stereo, TV, VCR, DVD, CD Players, Computer, Etc. How many times has one of these items broken down because of bad components? Not very often. They do break down because of abuse or misuse, but seldom due to bad or unreliable parts. My point is surface mount components are probably some of the MOST RELIABLE components in existance. If they weren't, most system manufacturers wouldn't be using them because they couldn't afford all the warranty returns that they would get if they weren't reliable. As long as you spec the component properly, and do a good job of installing the component, it probably will outlast you. How's that for reliable? :-) Hope I answered your question. Regards, Jim On Tue, 13 February 2001, Ken Robertson wrote: > > I was wondering, are SMD resistors/capacitors just as good as regular sized ones? I'm designing a circuit board and it's a bit tight on space. I'd like to use SMD parts to save space, but not sure if the quality or reliability is up to par. I mean, they are are so damn small! :) Just wanted to make sure. > > Thanks, > Ken > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. .....jimKILLspam@spam@jpes.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

I think you would be surprised how many parts are now SMD components with leads and then encapsulated. The nifty little 0.1uF caps are one that springs immediately to mind. The only reason to encapsulate them is to support the leads. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

At 08:59 AM 2/13/01 -0800, Ken Robertson wrote: >I was wondering, are SMD resistors/capacitors just as good as regular >sized ones? I'm designing a circuit board and it's a bit tight on >space. I'd like to use SMD parts to save space, but not sure if the >quality or reliability is up to par. I mean, they are are so damn small! >:) Just wanted to make sure. Absolutely. In fact, one of the biggest problems in assembly used to be bad solder joints, caused by the stress of trimming the leads. In theory, a good saw dosen't stress the joints, but in fact, what happens is that they tend to let the saws run longer than they ought to, and end up stressing the joints again. SMD, no leads, no stress, no problem. Make sure you have enough heatsinking for whatever power you might be dissipating though, with smaller bodies, and no leads to act as free heat sinks, some marginal designs will fail if ported directly to SMD. -- Dave's Engineering Page: http://www.dvanhorn.org Where's dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Alan B. Pearce wrote: > > I think you would be surprised how many parts are now SMD components with leads > and then encapsulated. The nifty little 0.1uF caps are one that springs > immediately to mind. The only reason to encapsulate them is to support the > leads. Generally SMT parts are pretty good. Mind you, I don't get to check many 10 year old SMT circuits, mainly newer ones. One problem we do see a lot of is SMT failures in TV remotes, these get a lot of flex and vibration. I assume the rigidly mounted brittle SMT parts (most are ceramic) don't handle the stretch and flex forces like the older style remotes with parts that have leads. I would probably consider heat expansion of the board and flex issues if designing from scratch with SMT parts. :o) -Roman -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

> -----Original Message----- > From: Alan B. Pearce [SMTP:.....A.B.PearceKILLspam.....RL.AC.UK] > Sent: Tuesday, February 13, 2001 5:52 PM > To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU > Subject: Re: [EE]: SMD as good as regular components? > > I think you would be surprised how many parts are now SMD components with > leads > and then encapsulated. The nifty little 0.1uF caps are one that springs > immediately to mind. The only reason to encapsulate them is to support the > leads. > Not seen these, all the 100n caps I've used have been 0603 ceramic packages with no sign of leads! I have seen quite a few tiny electrolytics mounted on a small plastic carrier to be used as an SMD device. Mike -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body

SMD outperform their legged friends in all regards excepting price and technician-friendliness (unless specialized tooling and training are available). There are some tricks related to high G environments but I don't know much about that. Peter -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email @spam@listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body