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Old 13th October 2012, 03:58 PM   #1651
bcarso is offline bcarso  United States
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Quote:
Originally Posted by qusp View Post
matching anything is tedious, no way around that. I wouldnt think it would be that bad, i'll let you know =) no I wouldnt think you would need to keep it there long to stabilize, given the size of the device/die I couldnt see it taking long to get up to temp
The 862s are generally pretty close to zero tempco at Idss, so stabilization is quite fast due to that as well.
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Old 13th October 2012, 06:39 PM   #1652
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I wonder if anybody's interested in a parallel effort to design a dedicated unity gain follower to complement the general purpose op amp?

Thanks,
Chris
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Old 13th October 2012, 06:56 PM   #1653
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You guys are complicating too much about matching rig for BF862 and other SOT23 devices. 2 crocodile clips will do the job. One clip across G and S and other clip on D. Example is bellow.
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Old 13th October 2012, 10:20 PM   #1654
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Quote:
Originally Posted by Chris Hornbeck View Post
I wonder if anybody's interested in a parallel effort to design a dedicated unity gain follower to complement the general purpose op amp?

Thanks,
Chris
Sounds great, propose some parameters.
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Old 13th October 2012, 11:15 PM   #1655
EUVL is offline EUVL  Europe
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> I wonder if anybody's interested in a parallel effort to design a dedicated unity gain follower to complement the general purpose op amp?

I already have umteen versions of those, some published and some not.
Jung diamond buffer, source follower with or without cascode, .....
Also DIP8 compatible and pin compatible with single or dual opamps on 10x10mm footprint.
You just need to tell me what you want.


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Old 13th October 2012, 11:42 PM   #1656
bcarso is offline bcarso  United States
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I wonder if anybody's interested in a parallel effort to design a dedicated unity gain follower to complement the general purpose op amp?

Thanks,
Chris
I've been working on extensions of the linuxguru buffer approach for a client who may not mind their being shared. However, the exemplary performance comes at a steep cost in quiescent power consumption, so they may be of limited appeal.
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Old 14th October 2012, 12:46 AM   #1657
qusp is offline qusp  Australia
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Quote:
Originally Posted by stormsonic View Post
You guys are complicating too much about matching rig for BF862 and other SOT23 devices. 2 crocodile clips will do the job. One clip across G and S and other clip on D. Example is bellow.
looks like more of a pain than pressing it down onto some pads, it would also seem to add unwanted thermal mass. It has the bonus of not having to hold them there though; well if you trust them and the attached cables not to snap little legs off if left to their own ..erm....devices (sorry).

though as bcarso mentioned for this part it has close to zero tempco @ idss, that may not be a big deal, at least for the bf862. think i'll stick to something like Scotts method, i'm sure with some thought some sort of mechanism could be found, but I dont thin I could be bothered at this stage.

Last edited by qusp; 14th October 2012 at 01:01 AM.
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Old 14th October 2012, 01:22 AM   #1658
rsavas is offline rsavas  Canada
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Default Preliminary Layout & Schematic

Crappy day outside, so I gave it a shot and have a schematic a preliminary parts placement. 0805 passives and top-sided only placement, at this point.Retained original ref des, to make it easy to follow. The schematic DOA-SW01.SchDoc has an error Q17 Emitters are tied to the "Out" net.

Rick
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Old 14th October 2012, 09:34 AM   #1659
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I do not mind high quiescent power - please post.



/S

Quote:
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I've been working on extensions of the linuxguru buffer approach for a client who may not mind their being shared. However, the exemplary performance comes at a steep cost in quiescent power consumption, so they may be of limited appeal.
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Old 14th October 2012, 09:45 AM   #1660
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I have attached below an audio preamplifier that can be the basis for achieving an operational amplifier with discrete components.

From experience, the solution presented below I would say that is the best balance between complexity and performance. Of course, the schedule can be complicated but that does not make sense. And if you are thinking complicated diagram, then choose a better operational in capsule, like OPA2134, LME49710 ...

Good luck to all.
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