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Old 27th November 2010, 04:51 PM   #21
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Originally Posted by abraxalito View Post
methinks someone didn't factor in the 101 factor of their distortion magnifier...
I just noticed that as well; it's fixed in version 1.02 of the datasheet released in back in late March (though some of the other issues still aren't). Overall it looks like an interesting part for DC servos--my shortlist there is the TL071, LME49880, and ADA4637. The 49880 fills the gap between the TL071 and ADA4637 rather nicely, though the TL071's plenty for the standard servo implementation where all the servo does is integrate.
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Old 29th November 2010, 02:07 AM   #22
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For servo duty, there are some newer TI offerings which look worthy. That is assuming that lowish noise and bias currents are desirable (they would be to me if I were seeking out a servo amp). OPAX141, OPAX376 and OPAX209. The latter is bipolar but has lower noise than any JFET I've seen coupled with commendably low input bias current for a bipolar. They're all considerably lower cost than the AD part you've mentioned though clearly dearer than the humble TL071.
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Old 29th November 2010, 12:55 PM   #23
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Yeah, nice parts, particularly with the SOT-23 availability in the single channel versions. Too bad the OPAx209's a RRIO and hence likely requires it's own set of rails in typical audio designs; particularly good specs there. For 15V rails the LMC6801 might be an interesting alternative.

So far I've found the TL071's quiet and low bias enough as an integrator. What usually pushes me away from it's need for speed and linearity characteristics more like an audio op amp. Haven't found a precision op amp with both those properties, though I haven't looked particularly hard.
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Old 30th November 2010, 09:14 AM   #24
Calvin is offline Calvin  Germany
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Hi,

whats RRIO?? The OPAx209 are specced for single or dual supplies of up to 36V/2x18V and the pin -layout of the MSOP and SOP-types is common style.
Why should they require a own set of supplies??
Look really interesting for Phono-stages

jauu
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Old 30th November 2010, 09:30 AM   #25
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RRIO = Rail-to-rail input and output.
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Old 30th November 2010, 12:36 PM   #26
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My bad; OPAx376's the RRIO.
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Old 30th November 2010, 01:15 PM   #27
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The OPAx376 is CMOS, limited to 5.5V supply. The thing to watch with these low noise CMOS amps with rail-rail inputs is that the full CM input voltage range isn't usable for audio (i.e. with low distortion) so they ain't really RRI. This TI part is better than most, it can go to about 1V below the positive rail before distorting. One of Maxim's similar parts (MAX4475) doesn't do half as well though its noise is even better. The headline low distortion figures (which, let's face it, are pretty impressive) are only achieved when keeping within this CM input voltage limit.
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Old 29th March 2011, 03:56 PM   #28
qusp is offline qusp  Australia
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lme49990 = winner by a mile and ad797 has been my favorite chip for years. i'm yet to try it out in any regulator designs, 797 was also incredibly versatile; but i surely will. so far i have used it in simple iv and in opc's 'the wire' headphone amp with balanced input and lme49610 in the se output. this combo is killer, best sound i have ever heard from chips and owens name for his amp is entirely apt

Last edited by qusp; 29th March 2011 at 03:58 PM.
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Old 30th May 2011, 06:28 PM   #29
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Hello

Where to buy the LME49990
I don't find it on Ebay !!

Serge
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Old 30th May 2011, 06:45 PM   #30
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Quote:
Originally Posted by Sergelisses View Post
Hello

Where to buy the LME49990
I don't find it on Ebay !!

Serge
Digikey, Avnet, Future Electronics, Arrow Electronics all carry the part.
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