I apologize for the poll. I'm not a fan of them either. In this case, however, I am genuinely curious to see the data.
Assuming you have two options:
1) High-performance amplifier build using leaded (thru-hole) components.
2) High-performance amplifier build using SMD (surface mount) components such as SOIC and 0805 or larger passives.
The two builds would provide identical measured performance, but the surface mount option would likely be a slightly smaller board. The cost of parts and boards would be the same for the two options.
What's your preference?
Thanks in advance.
Tom
Assuming you have two options:
1) High-performance amplifier build using leaded (thru-hole) components.
2) High-performance amplifier build using SMD (surface mount) components such as SOIC and 0805 or larger passives.
The two builds would provide identical measured performance, but the surface mount option would likely be a slightly smaller board. The cost of parts and boards would be the same for the two options.
What's your preference?
Thanks in advance.
Tom
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Having the proper tools makes a huge difference. I use a small (1.0 mm) chisel tip on my soldering iron and 0.5 mm diameter solder.
For two-terminal parts, such as resistors, I wet one pad with solder, set the component on the footprint, reflow the solder, and wait for it to cool. Then I solder the other side and touch up the first side if need be.
For ICs, I solder two corner pins diagonally opposite from each other using the same method as for two-terminal devices. Once the IC is centred on the footprint, I solder the remaining pins and touch up the first two if need be.
Folks with older eyes (and I reluctantly admit that I'm starting to enter that category) will benefit from picking up a pair of reading glasses. If you want to get real fancy, a dissecting microscope can be a worthwhile investment.
Tom
For two-terminal parts, such as resistors, I wet one pad with solder, set the component on the footprint, reflow the solder, and wait for it to cool. Then I solder the other side and touch up the first side if need be.
For ICs, I solder two corner pins diagonally opposite from each other using the same method as for two-terminal devices. Once the IC is centred on the footprint, I solder the remaining pins and touch up the first two if need be.
Folks with older eyes (and I reluctantly admit that I'm starting to enter that category) will benefit from picking up a pair of reading glasses. If you want to get real fancy, a dissecting microscope can be a worthwhile investment.
Tom
Well, I don't have strict preference. Thru-hole are usually easier to handle. I've lost few surface components somewhere on desk 
Soldering SMD is not that hard and even with a bit of practise can be faster to solder as you don't need to cut leads. And as Daniel noticed lately lots of new interesting parts are SMD only - like big ceramic capacitors, Panasonic PPS caps, affordable 0.1% resistors or SOIC ICs.
Soldering SMD is not that hard and even with a bit of practise can be faster to solder as you don't need to cut leads. And as Daniel noticed lately lots of new interesting parts are SMD only - like big ceramic capacitors, Panasonic PPS caps, affordable 0.1% resistors or SOIC ICs.
Up to 805 and soic size, smd is quite easy. The only downside is when you need to rework the board, it's a bit more complicated ime. But for a project you're not supposed to modify, smd is nice. It also allows shorter loops, etc.
@JonSnell: doesn't leaded solder with 2% silver prevent leaching ? It's easier to get good joints from leaded solder than from lead free, at least with hand soldering.
@JonSnell: doesn't leaded solder with 2% silver prevent leaching ? It's easier to get good joints from leaded solder than from lead free, at least with hand soldering.
Having built most of opc's The Wire amplifiers I really don't see any issues building SMD stuff without anything too fancy at all.
Soldering QFN (or anything needing a power pad) and anything smaller than 0603 is a pain in the *** but mostly doable by hand, with a relatively inexpensive hot air rework tool (ebay ~$60 or so). SOIC + 1210 or 0805 is really quite easy and with a little practice quicker to build.
Chris
Soldering QFN (or anything needing a power pad) and anything smaller than 0603 is a pain in the *** but mostly doable by hand, with a relatively inexpensive hot air rework tool (ebay ~$60 or so). SOIC + 1210 or 0805 is really quite easy and with a little practice quicker to build.
Chris
... and also what components are likely to contain susceptible silver?
As of this morning, silver is 100x the cost of copper. So, there would need to be some extremely highly-specialized reason for a manufacturer to choose silver.
Completely agree. I'm curious as to how folks feel about selective inclusion of 0603s on a majority SOIC + 1206 + 0805 board.
Stencils and reflow ovens are getting fairly inexpensive. Be some time before it's common for individual DIYers to have them. But I'd expect any reasonably electronics oriented maker space to have such kit. The missing piece seems to be pick and place; I'm aware of a few low cost projects in that direction but it'll be some time to maturity.
As long as we're talking about DIY SMD like 0805-1210 and SOIC packages like an opamp's, it's easier and quicker to build than with through hole parts.
My DIY amp designs include a mix of through hole and SMD parts. Through hole resistors and capacitors find their uses in something like a LM317/337 PSU, local decoupling, etc. For the rest I've moved on to SMD parts. You can't beat having an amp laid out in a few square centimeters, ceramics right at a device's power pins, and lots of extra benefits of going SMD.
More elaborate packages with denser pins could be a pain if not careful.
My DIY amp designs include a mix of through hole and SMD parts. Through hole resistors and capacitors find their uses in something like a LM317/337 PSU, local decoupling, etc. For the rest I've moved on to SMD parts. You can't beat having an amp laid out in a few square centimeters, ceramics right at a device's power pins, and lots of extra benefits of going SMD.
More elaborate packages with denser pins could be a pain if not careful.
Soldering QFN by hand is not a fun task. We had one guy where I used to work who could do it reliably. Even he only achieved about 80 % yield. We ended up buying a METCAL QFN/BGA rework station to address the need for swapping out parts.
Power pads on SOIC-type packages is not too bad to solder by hand, especially if the power pad is brought through the board to the bottom layer as well. Then just remove the solder mask on the bottom and solder the DAP from the bottom. It's a hack, but it works.
Tom
I'm totally okay with it, though I have slipped with the tweezers and lost a few 0603 caps before, dunno why they're just a bit more likely to get away, rarely have dramas with the bigger stuff, even still it's not too often and I do like the layout a bit more if the decoupling can be done with 0603.
I've got a kit to convert a toaster oven to reflow oven here ... really should clear that corner out and set that oven up actually, thanks for the reminder of another almost finished project that has been sitting on the shelf
I did see a kit benchtop pick and place around somewhere on the net last year, was planning on waiting to see a few people test it out before deciding if I should look more closely.
That's good to hear; thanks for the feedback.
My reflow oven project remains not started. I've a few projects where I'd like to use QFNs, WLCFPs, and some larger thermal pad packages that'd likely be a bit tricky using the underside approach Tom mentions. But the ones I'm currently working on are all 0603+ and SOIC. Considering current rates of improvement it makes sense to wait on reflow kit until I'm actually close to having "next gen" boards to populate.
My reflow oven project remains not started. I've a few projects where I'd like to use QFNs, WLCFPs, and some larger thermal pad packages that'd likely be a bit tricky using the underside approach Tom mentions. But the ones I'm currently working on are all 0603+ and SOIC. Considering current rates of improvement it makes sense to wait on reflow kit until I'm actually close to having "next gen" boards to populate.
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