Unfortunately, it wasnt a common/standard topology. Took me <1 hour to breadboard. How long to do the pcb route? It is substantial in time and cost... Iterations or changes are harder as well.
There is no way to do breadboarding with SMD. So, I stay with TH for audio to HF.
THx-RNMarsh
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2 layer boards are pretty cheap and fast from Sunstone and others. Unfortunately this is the only truly representative way that I know of.
Everytime I do an ExpressPCB run I have a file full of adapters that I cut and paste into all the unused margins. Really all you need is a small SOT-23 to TO-92 most of the time for discrete transistors. I don't see this adding any more parasitics than the leads would in the first place.
You can mount smt parts on adaptor pcbs, and then they can plug right in. There are many different kinds avaiiable.
Capital Advanced Tech Standard products Especially these. http://www.capitaladvanced.com/33000ser.htm
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some 20 years ago I tried to breadboard CFA op-amps. It didn't end spectacularly well and had some oscillations that made it noisy even when powered off batteries. Lesson learned and parked until I had time to look at it with the proper test tools. Which of course never happened. I honestly don't think you will find out 'how well' a lot of modern parts will work without doing a board. But I was never skilled in the art of dead bug prototypes.
And back then I was arrogant enough to ignore the warnings in the data sheet about how easily you could make it oscillate.
Those are 200MHz opamps, they might be a little pernickety?
And back then I was arrogant enough to ignore the warnings in the data sheet about how easily you could make it oscillate.
Those are 200MHz opamps, they might be a little pernickety?
I used an adapter board recently for an SO-8 packaged OPA1632 and had bypassing as close as I could get it on the ground-plane board below the adapter board. I couldn't see any outright oscillations with a 100MHz scope, but the distortion versus level was much worse at higher signal levels than the specification said I should see. I eventually patched some 0805 100nF caps onto the adapter board itself and things got much better, although still not that close to the datasheet.
I agree that one may not see the real performance until you have a real board and decent layout, if the parts have large gain-bandwidths.
Headers are the easy part for OPamp or transistor. But changing out R's and C's and additional circuitry etc makes smd bread-boarding a new design idea or just to test under various scenarios, impractical. Not that it cannot be done.... but impractical.
I expected possible osc. I also knew I didnt need the full BW... so I killed some of the BW and took stability instead. [and local PS bypass at pin]
Works fine.
Now that I have the info and data that I wanted and if I now wanted to make it with pcb and ground plane etc.... I could go ahead with some knowledge that what I wanted, I'll get. And, maybe use smd.
The desirability of portable gear and more features with smarts in them creates a big demand for smd. And greater circuit integration.
However, as long as other electronics requires higher voltages, currents and Watts than small rechargable battery powered hand-held devices, there will be a need for TH parts.
THx-RNMarsh
I expected possible osc. I also knew I didnt need the full BW... so I killed some of the BW and took stability instead. [and local PS bypass at pin]
Works fine.
Now that I have the info and data that I wanted and if I now wanted to make it with pcb and ground plane etc.... I could go ahead with some knowledge that what I wanted, I'll get. And, maybe use smd.
The desirability of portable gear and more features with smarts in them creates a big demand for smd. And greater circuit integration.
However, as long as other electronics requires higher voltages, currents and Watts than small rechargable battery powered hand-held devices, there will be a need for TH parts.
THx-RNMarsh
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When I did some work in 2014 for a smart home product, I got the initial boards that had been fabricated in China. At first glance I couldn't see anything except the SOT-23 transistors and a few small ICs. With sufficient magnification I finally made out the resistors and capacitors, most of them 0201. I didn't bother trying to change any of them, but in some cases removed particular ones and figured out other places to attach different and larger parts. After a while SOT-23 packages began to look rather large.
A friend of mine, who's still hanging on doing home audio electronics repair, does some amazing things with multileggers. A modern surround receiver converts all audio to digital and runs it through the same board that does HDMI switching. What could possibly go wrong?
Some billion-leggers have soldered connections on the *bottom*. I wouldn't have believed it if not shown in person.
Rage, rage against the dimming of my sight.
All good fortune,
Chris
Some billion-leggers have soldered connections on the *bottom*. I wouldn't have believed it if not shown in person.
Rage, rage against the dimming of my sight.
All good fortune,
Chris
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When integrated circuits of the DIP variety began to be used, my father stated that in his opinion they would never be practical because they were too small. He'd grown up putting ham radio equipment together, and had viewed transistors with grave suspicion. But he gradually adopted them, even though his understanding of thermal requirements remained somewhat hazy.
Eventually he was told that certain of his switching modules looked antiquated, so he replaced most of the discrete transistors with transistor arrays in DIP packages.
Eventually he was told that certain of his switching modules looked antiquated, so he replaced most of the discrete transistors with transistor arrays in DIP packages.
Thats marketing.... it is a CFA with a buffer on the low Z CFA input to make that port high Z also. behaves like a CFA though internally. Very useful fix to the High-Low input Z problem of CFA. Expect to see more of these.
---- two LM7171 in series.... THD at -120 . Pretty good. IMO. 100mA output. 4500 v/usec SR isnt too bad, either.
THx-RNMarsh
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Linear Technology has a few of those too, for example LT1363 - http://cds.linear.com/docs/en/datasheet/1363fa.pdf
No it's an H bridge amplifier OLD, OLD news, please keep up with what's going on.
...... it appears as CFA in the gain behavior department (and the diagram on page one of data sheet).
Such design as I described (buffer to low Z of CFA) has also been tried here by others in SIM with discrete's. Works very well there, too BTW.
I'll try the LT also. Because these 7171's are expensive. Page 11 of the LT data sheet shows the CFA with buffer on the low z input topology.
I'm peddling as fast as I can, Scott. Maybe its those training wheels that are slowing me down.
THx-RNMarsh
Such design as I described (buffer to low Z of CFA) has also been tried here by others in SIM with discrete's. Works very well there, too BTW.
I'll try the LT also. Because these 7171's are expensive. Page 11 of the LT data sheet shows the CFA with buffer on the low z input topology.
I'm peddling as fast as I can, Scott. Maybe its those training wheels that are slowing me down.
THx-RNMarsh
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LM6172 which is a slightly slower, lower power but dual version of your LM7171 is relatively affordable here. Over on TI's website its $1.60/1k.
😎🙂 May be even more stable... esp at low gain.
Thank the Gods I can still try things with a bread-board. I hope to be dead if and when I cant use TH any more.
THx-RNMarsh
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I'd caution against breadboarding them on that prototyping board you showed in the pic, they're not the easiest of opamps to get the decoupling right. When I used them in unity gain in an active XO I had mine oscillate until I'd tweaked the decoupling. They do need loving care and attention to keep stable and those plug-in boards tend to have rather high inductance.
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