Frederick Vinton Hunt Harvard 1939Can you spell Cascode?
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Was this the daddy of todays leadless SMD packages?
Yes that's the one. That package was a problem, sort of custom because our QA dept refused to deal with the vendors of cheap automotive SIP's. Believe it or not our cost was $0.95 at the 100k level, killed margins. I have played 8 Ohm bookshelf speakers with these (the sound of the thermal shutdown going off and on was something else).
BTW Walt J's 823/815 composite amp is a great line/headphone stage.
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Some sources are "matched" compl only by their dc parameters - like Vbe and arent remotely alike for hfe or much of anything else. Some to92 compliments from NTE are like this. So, just noting that 'matched pair' can mean just about anything from mfr to mfr. Same breakdown and ft are hardly what we need for low distortion so finding matched pairs on the curve tracer is a good starting point.
THx-RNMarsh
RNMarsh,
This is exactly why I asked earlier if there are times when devices from different manufacturers could actually be the better match between devices. Matching the parameters that are important to you rather than something that really won't be the most effective for an audio application.
This is exactly why I asked earlier if there are times when devices from different manufacturers could actually be the better match between devices. Matching the parameters that are important to you rather than something that really won't be the most effective for an audio application.
> Some to92 compliments from NTE are like this.
NTE is a supplier, not a manufacturer. I would
not use them as any kind of referance.
@ Kindhornman:
I still maintain my original stance on this question
http://www.edn.com/design/analog/4407476/Successfully-choose-complementary-bipolar-transistors
2n3904 - 2n3906
http://www.fairchildsemi.com/search...al|mode+matchallpartial&&Nty=1&&showAll=false
NTE is a supplier, not a manufacturer. I would
not use them as any kind of referance.
@ Kindhornman:
I still maintain my original stance on this question
http://www.edn.com/design/analog/4407476/Successfully-choose-complementary-bipolar-transistors
2n3904 - 2n3906
http://www.fairchildsemi.com/search...al|mode+matchallpartial&&Nty=1&&showAll=false
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Hitsware,
Okay, but Scott's earlier comment made it sound like the matching even what is being done is not really much of a match except at a very narrow range of value. Doesn't sound like any true complementary devices between NPN and PNP really exist even from the same manufacturer due to the process and plain old physics.
Okay, but Scott's earlier comment made it sound like the matching even what is being done is not really much of a match except at a very narrow range of value. Doesn't sound like any true complementary devices between NPN and PNP really exist even from the same manufacturer due to the process and plain old physics.
Same story on 2N3906/3904 hoe's very different.
BTW I don't get the big deal, designs should not need obsessive matching.
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I am fairly certain that I didnt use them as a reference part rather an example of what is called a compl pair by the seller/mfr. And, that compli seems to mean different things to different mfrs. You can not just go by mfr suggestion as to what are compli for low distortion audio. There are some N-P types which are excellent compli but are not in same package/wattage rating... but as small signal devices, its OK.
Thx-RNMarsh
I did. "Did you send another?
ps.I looked, it's also missing from my outbox. I've no idea what happened. responded again.
jn
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"Yes that's the one. That package was a problem, sort of custom because our QA dept refused to deal with the vendors of cheap automotive SIP's. Believe it or not our cost was $0.95 at the 100k level, killed margins. I have played 8 Ohm bookshelf speakers with these (the sound of the thermal shutdown going off and on was something else)."
Cheap automotive?We have a billion $ plus biz in that segment and it drives quality throughout the org to unbelievably high standards. AEC100 on power devices - tough to get through. Maybe you mean cheap sub cons - that's a totally different kettle of fish
Cheap automotive?We have a billion $ plus biz in that segment and it drives quality throughout the org to unbelievably high standards. AEC100 on power devices - tough to get through. Maybe you mean cheap sub cons - that's a totally different kettle of fish
General comment for others:
Matching is more of an issue with finding good compliments in less than very high gnfb designs. Or some form of cancellation technique. Do you have any cancellation tech that you can share?
Thx-RNMarsh
Cheap automotive?We have a billion $ plus biz in that segment and it drives quality throughout the org to unbelievably high standards. AEC100 on power devices - tough to get through. Maybe you mean cheap sub cons - that's a totally different kettle of fish
I had no say so don't know. I brought a very servicable automotive audio power amp from ST into the packaging dept as an example and they said simply, "We don't deal with those vendors". They would have been refering to package sub cons in that case, yes.
The AD797 contains about as much cancellation by symmetry as you will find.
If you could get at all the internals you would find you could make a low GNFB version also. The IP has expired BTW.
Dick thought about it some more, a Quinn cas-comp input and the 797 second stage would make an interesting amp.
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