I have seen Mr. Larkin post a few example photos of breadboards using copper-plated FR4 cut with a dremel tool. I'm thinking about trying this myself.
I am in the habit of doing deadbug-style using 28 or 30 AWG and taping the whole thing to a bare piece of FR4 as I go:
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Soldering SOT23 and SC70 parts this way requires some finesse, and some days I'm quicker at it than others... the above example probably took me around 2 hours. Seems like I should be faster than that.
John, what are your tips/tricks for doing the dremel technique?
Does anyone else here have any good breadboard techniques I should be aware of?
Use surface-mount adapters for most parts. Stick them down with double-stick foam tape.
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I use 0.062 thick 1 oz copperclad FR4. 2 oz is horrible to Dremel. I really like it to be gold plated, so it looks great, doesn't tarnish, and solders beautifully. I think you can get some on ebay or Amazon. I have a PCB house plate me a couple square feet every year or so. Shine it up with SoftScrub and it looks like jewelry.
Get a variable-speed Dremel and some rounded-end carbide dental burrs. Cheap on ebay.
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I whiteboard my schematic and circuit layout then draw lines on the copperclad with a straightedge and a Sharpie, then cut the lines with the Dremel. Trim with an x-acto. It takes a bit of practise to get good. I put the board flat on the bench, rest my wrist on the bench, and cut freehand under a Mantis magnifier.
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Leave the bottom mostly ground plane. Connect topside ground islands with wire vias or 2-56 screws and nuts, or edge-launch connectors. The screws are good places to clip on power supplies and scope probe grounds. (Cut a circle out of the back side to not short non-ground things out! I keep forgetting to do that.)
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Really fast stuff has to be matched impedance, no sockets or adapters.
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I keep the breadboards basically forever. I assign a drawing number to each one and document it (mostly photos) and test results. That's kept on a shared "protos" folder on a server. Some are actually PCB layouts. Other people can log a drawing number and post their stuff too. It's a great long-term resource.
Tomorrow I plan to test a tiny LVDS line receiver for some unspecified things.
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John Larkin Highland Technology, Inc
The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Excellent. Thanks for the details. I'll give it a go and report back. This should work particularly well for power circuits, since I can play around with the amount of copper for heat sinking.
Yes, I have several. I also have a few working and non-working HP35's, which I don't use.
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John Larkin Highland Technology, Inc
The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Most breadboards start with a bag of parts and grow like a yard full of weeds. One nice thing about the Dremel style is that it forces you to plan. The stop, think thing again.
A small SOT89 or SOT223 fet can dissipate maybe 3 watts on a couple of square inches of 1 oz copper. You could add heat sinking in interesting ways. I don't have analytical tools for thermal analysis, so I experiment a lot.
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John Larkin Highland Technology, Inc
The cork popped merrily, and Lord Peter rose to his feet.
"Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
Sea moss, looking at your proto you seem to be missing the first point of copper clad. And that is to having all your grounds tacked to the copper on the board.. the copper clad is your ground plane, and you (I) build on top of that.
John L's stuff is pretty, but he doesn't show you the ground plane on the bottom (he doesn't show it, because we all know it's there.)
Those are bits of double-sided copperclad, probably super-glued to the main board. I ran this at low pulse rates for testing, so didn't need serious heat sinking.
For serious heat sinking, you can hang a TO- or Dpak off the edge of the board, onto a metal plate or block.
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An 0.062" thick aluminum nitride insulator works great.
It's good to bolt these little boards to something heavy anyhow.
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
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