Through Hole vs. Surface Mount
in [Design]
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From: JosephKK on 31 Mar 2010 15:07 On Mon, 29 Mar 2010 11:17:51 -0500, Jim Yanik <jyanik(a)abuse.gov> wrote: >Hammy <spam(a)spam.com> wrote in >news:9fc1r5p8f21dgh6htq6lpf6ts4tf1ij0dt(a)4ax.com: > >> On Mon, 29 Mar 2010 08:10:39 -0500, Jim Yanik <jyanik(a)abuse.gov> >> wrote: >> >>>Robert Baer <robertbaer(a)localnet.com> wrote in >>>news:xLqdnSAtgJGa0S3WnZ2dnUVZ_oQwAAAA(a)posted.localnet: >>> >>>> Chris wrote: >>>>> I have just completed a designing a board that has 5 16 pin ICs. I >>>>> was planing on etching and drilling myself, but after my last >>>>> project took for ever to drill far fewer holes, I was considering >>>>> going surface mount. I am only planing to make three at first. >>>>> Should I stick to through hole for the ease of hand soldering, or >>>>> should I switch to decaf and wait a month and try my hand at >>>>> surface mount. >>>>> >>>>> Comments Welcome, >>>>> Chris Maness >>>> If you are young (good eyes), the smallest parts to use would be >>>> 0402. That said, fine pitch QFPs are not a big problem if pads are >>>> pre-tinned. >>>> >>> >>>making a one-off PCB to use fine pitch ICs is the real problem. >>> >>>I have a project on hold until I can figure out how to make a PCB for >>>a 8 pin eMSOP package,LM3410XMY. the entire IC is about the size of a >>>pencil eraser. :-( >>> >>>(It's a boost LED driver-regulator,1 IC and 7 other parts,all 0603 >>>size) >> >> I use the TPS40210-11 Boost controller in 10 pin MSOP with powerpad. >> They aren't that bad. Drill one or two holes under the IC put light >> solder under the IC, and a dab of solder on the power pad. The parts >> are so tiny you can heat the exposed copper pore on either side of the >> IC causing the solder on the power pad to reflow. The other way is >> heat the wires you use for vias under the IC to reflow the solder.Just >> dont go crazy with the solder under The IC or when it settles it will >> push the solder on the pads; short phhsst! >> >> The only thing about those parts if you suspect it's damaged there's >> no easy way to swap it out without damaging all the pads and traces. >> Doable with the right tools, hot-air soldering tool, 5 mil nickel wire and desolder the power pad last. > >my problem isn't in soldering the IC,but in laying out and etching a PCB >with such fine pitch leads. (I had thought the IC would be bigger...) > >Also,I was mistaken about the 603 size,they are 805,except for the coil and >diode. I too would find nearly 40 pins to the inch (0.65 mm c-c) rather daunting.
From: Joerg on 31 Mar 2010 16:25 John Devereux wrote: > Joerg <invalid(a)invalid.invalid> writes: > >> Archimedes' Lever wrote: >>> On Tue, 30 Mar 2010 09:42:05 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> All I can tell you is that there is no glop. I just did a few more >>>> solder joints and held them under a magnifier -> nada, zilch, >>>> clean. >>>> >>>> Maybe you used the wrong temperature? My Weller is running at 640F >>>> right now. >>> >>> Most 'no-clean' hand operations I ever saw left the perfectly formed >>> solder joint encapsulated in a thin flux film. Are you sure that you are >>> not just too old or too non-detail oriented to 'see' it, even though it >>> is there? >>> >>> The flux does not evaporate, and is, by design, meant to remain, so it >>> *has* to be there... literally. >> >> Ok, but it hasn't corroded or otherwise tainted one lone solder joint >> in years. If it does cause a failure 300 years down the road I think I >> could live with that :-) > > We use it for everything, never had a problem either. > > I take "no-clean" to mean "do not clean". I have heard (here) of > problems when cleaning is attempted, the insulating component is washed > away leaving an ionic residue which can absorb water and conduct. Or > something. > Even then I had no problems. Many times in my lab I lash up jigs, on Monday for example a tester to run transformers at 50Hz, 60Hz, 400Hz or wherever. That stuff gets a beating over time, alligator clips are attached to soldered areas over and over again so things become scraped. Never a problem. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 31 Mar 2010 16:28 Robert Baer wrote: > Joerg wrote: >> Robert Baer wrote: >>> Joerg wrote: >>>> Robert Baer wrote: >>>>> Joerg wrote: >>>>>> Robert Baer wrote: >>>>>>> Joerg wrote: >>>>>>>> Martin Riddle wrote: >>>>>>>>> "Chris" <christopher.maness(a)gmail.com> wrote in message >>>>>>>>> news:fbd910e4-f10e-42d8-a193-bb9c7a1cd19f(a)c2g2000pre.googlegroups.com... >>>>>>>>> >>>>>>>>>> I have just completed a designing a board that has 5 16 pin >>>>>>>>>> ICs. I >>>>>>>>>> was planing on etching and drilling myself, but after my last >>>>>>>>>> project >>>>>>>>>> took for ever to drill far fewer holes, I was considering going >>>>>>>>>> surface mount. I am only planing to make three at first. >>>>>>>>>> Should I >>>>>>>>>> stick to through hole for the ease of hand soldering, or should I >>>>>>>>>> switch to decaf and wait a month and try my hand at surface >>>>>>>>>> mount. >>>>>>>>>> >>>>>>>> >>>>>>>> A glass of Guinness works much better :-) >>>>>>>> >>>>>>>> >>>>>>>>>> Comments Welcome, >>>>>>>>>> Chris Maness >>>>>>>>> >>>>>>>>> I second the SMT try. It's not as difficult as it seems. Get >>>>>>>>> a good magnifier , headband type. >>>>>>>>> A good pair of tweezers, fine tips for your iron, and fine >>>>>>>>> 0.015" solder helps too. >>>>>>>>> >>>>>>>> >>>>>>>> I like 0.015" Kester No-Clean best. No mess. >>>>>>>> >>>>>>>> >>>>>>>>> There are some good parts out there that only come in SMT. >>>>>>>>> >>>>>>>> >>>>>>>> Yep, like tons of great RF transistors or fast opamps. >>>>>>>> >>>>>>> "No-Clean"? GACK! avoid that junk like the plague it is... >>>>>> >>>>>> >>>>>> I've had no issues at all with it. Very clean solder joints, and >>>>>> they stay clean. >>>>>> >>>>> 1) What do you use to clean the glop off? >>>> >>>> >>>> There is no glop. >>> * Interesting; Absolutely nothing but solder, nothing to remove >>> oxides, etc?? Then it DOES NOT CLEAN and so that is why it is called >>> "no clean"?? >>> >> >> All I can tell you is that there is no glop. I just did a few more >> solder joints and held them under a magnifier -> nada, zilch, clean. >> >> Maybe you used the wrong temperature? My Weller is running at 640F >> right now. >> > I do not and have never tried "no clean" as there were too many horror > stories. Well, all I can tell you is that I use it for years, so do clients, and there are no horror stories in this here neck of the woods :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Joerg on 31 Mar 2010 16:30 Robert Baer wrote: > Archimedes' Lever wrote: >> On Tue, 30 Mar 2010 09:42:05 -0700, Joerg <invalid(a)invalid.invalid> >> wrote: >> >>> All I can tell you is that there is no glop. I just did a few more >>> solder joints and held them under a magnifier -> nada, zilch, clean. >>> >>> Maybe you used the wrong temperature? My Weller is running at 640F >>> right now. >> >> >> Most 'no-clean' hand operations I ever saw left the perfectly formed >> solder joint encapsulated in a thin flux film. Are you sure that you are >> not just too old or too non-detail oriented to 'see' it, even though it >> is there? >> >> The flux does not evaporate, and is, by design, meant to remain, so it >> *has* to be there... literally. > Check! > That is the glop i was talking about. Then why doesn't anything corrode out here? Even stuff where there is extensive scratching by alligator clips never developed a problem. Now RoHS solder, that's a whole 'nother story. Don't get me started ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: krw on 31 Mar 2010 18:57
On Wed, 31 Mar 2010 13:30:12 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Robert Baer wrote: >> Archimedes' Lever wrote: >>> On Tue, 30 Mar 2010 09:42:05 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> All I can tell you is that there is no glop. I just did a few more >>>> solder joints and held them under a magnifier -> nada, zilch, clean. >>>> >>>> Maybe you used the wrong temperature? My Weller is running at 640F >>>> right now. >>> >>> >>> Most 'no-clean' hand operations I ever saw left the perfectly formed >>> solder joint encapsulated in a thin flux film. Are you sure that you are >>> not just too old or too non-detail oriented to 'see' it, even though it >>> is there? >>> >>> The flux does not evaporate, and is, by design, meant to remain, so it >>> *has* to be there... literally. >> Check! >> That is the glop i was talking about. > > >Then why doesn't anything corrode out here? Even stuff where there is >extensive scratching by alligator clips never developed a problem. > >Now RoHS solder, that's a whole 'nother story. Don't get me started ... We use RoHS solder and a no-clean flux. Hows that grab ya'. ;-) |