Through Hole vs. Surface Mount
in [Design]
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From: Robert Roland on 29 Mar 2010 12:35 On Mon, 29 Mar 2010 04:33:38 -0700 (PDT), "dcaster(a)krl.org" <dcaster(a)krl.org> wrote: >What about circuits that use a PIC that needs to be programmed where >the PIC can not be programmed in place? I would try VERY hard to avoid that. I can't imagine a situation where it should be particularly difficult to implement ICSP. Worst case, put the PIC in a socket and the rest of the parts on the surface. >I was all set to use surface >mount on a project and then started thinking about how many holes I >would still have to drill. Yes, most SMD projects do need some holes. >It seemed like I would still have to drill >about half of the connections. Well, you reduced the number of holes by half. As a bonus, you reduced size, weight and cost. A pretty good deal, if you ask me. Usually, you can't eliminate all the holes, but reducing the count is a good thing, especially if you are hand drilling. -- RoRo
From: Nico Coesel on 29 Mar 2010 13:12 "Martin Riddle" <martin_rid(a)verizon.net> 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. >> >> Comments Welcome, >> Chris Maness > >I second the SMT try. It's not as difficult as it seems. Get a good >magnifier , headband type. >fine tips for your iron, and fine 0.015" solder >helps too. Thats exactly the wrong way. Fine pitch is best soldered using a think flat soldering tip and flux. Its faster and it works better. -- Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico(a)nctdevpuntnl (punt=.) --------------------------------------------------------------
From: Don Klipstein on 29 Mar 2010 14:16 In article <Xns9D4A7D28794B9jyaniklocalnetcom(a)216.168.3.44>, Jim Yanik 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. >> > >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 would think ExpressPCB is plenty capable of this. That can lay out SSOP ICs with .025 inch pitch, also custom pads. - Don Klipstein (don(a)misty.com)
From: Hammy on 29 Mar 2010 14:32 On Mon, 29 Mar 2010 18:16:44 +0000 (UTC), don(a)manx.misty.com (Don Klipstein) wrote: >> >>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 would think ExpressPCB is plenty capable of this. That can lay out >SSOP ICs with .025 inch pitch, also custom pads. > > - Don Klipstein (don(a)misty.com) Well I would hope so are they may want to get out of the PCB business;-). What's the concern with laying out an etching? I do 0.0256 pitch regularly using the toner transfer method.
From: Fred Bartoli on 29 Mar 2010 16:34
Fred Abse a �crit : > On Mon, 29 Mar 2010 17:12:47 +0000, Nico Coesel wrote: > >> Thats exactly the wrong way. Fine pitch is best soldered using a think >> flat soldering tip and flux. Its faster and it works better. > > Chacun � son go�t! > Whoa! You'll get plonked by JT for that... -- Thanks, Fred. |