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<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Nice.<br>
I use the OPA1678 as my new working horse for quite a while now. <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span
lang=EN-GB style='font-size:12.0pt;color:black'>From: </span></b><span
lang=EN-GB style='font-size:12.0pt;color:black'>Synth-diy <</span><a
href="mailto:synth-diy-bounces@synth-diy.org" target="_blank"><span lang=EN-GB
style='font-size:12.0pt'>synth-diy-bounces@synth-diy.org</span></a><span
lang=EN-GB style='font-size:12.0pt;color:black'>> on behalf of Mattias
Rickardsson <</span><a href="mailto:mr@analogue.org" target="_blank"><span
lang=EN-GB style='font-size:12.0pt'>mr@analogue.org</span></a><span lang=EN-GB
style='font-size:12.0pt;color:black'>><br>
<b>Date: </b>Thursday, 19 April 2018 at 14:16<br>
<b>To: </b>Tim Ressel <</span><a href="mailto:timr@circuitabbey.com"
target="_blank"><span lang=EN-GB style='font-size:12.0pt'>timr@circuitabbey.com</span></a><span
lang=EN-GB style='font-size:12.0pt;color:black'>><br>
<b>Cc: </b>Synth DIY <</span><a href="mailto:synth-diy@synth-diy.org"
target="_blank"><span lang=EN-GB style='font-size:12.0pt'>synth-diy@synth-diy.org</span></a><span
lang=EN-GB style='font-size:12.0pt;color:black'>><br>
<b>Subject: </b>Re: [sdiy] Happenin' new opamp</span><span lang=EN-GB><o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB> <o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>I'm throwing in some news (for me at least) about the fairly new
OPA1678/79 low-noise </span><a
name="m_-5780210040590118938__MailOriginalBody"></a><span lang=EN-GB
style='font-size:12.0pt;font-family:"Arial","sans-serif";color:#222222;
background:white'>rail-to-rail</span><span lang=EN-GB> </span><span lang=EN-GB
style='font-size:12.0pt;font-family:"Arial","sans-serif";color:#222222;
background:white'>FET-input </span><span lang=EN-GB>op-amps that I was trying
as substitutes for the OPA1652/54, which has a price more than twice as high.
The specifications are remarkably similar, and by accident I got in contact
with TI's </span><span lang=EN-GB style='font-size:12.0pt;font-family:
"Arial","sans-serif";color:#222222;background:white'>John Caldwell. He writes:</span><span
lang=EN-GB><o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>"I’ll let you in a on a little secret, the silicon is identical
between the two devices. OPA1652 was released by another engineer before me,
and when I took over the portfolio of audio op amps I personally felt that
OPA1652 was too expensive to address the bulk of audio opportunities. For that
reason, we made some changes to the production testing (used new test hardware
that let us test more units faster) to reduce the manufacturing cost and
re-released the device at a lower price point.<br>
Fun fact: the OPA1652 / OPA1678 has the lowest broadband voltage noise of any
FET-type input amplifier in TI’s portfolio. It even has lower broadband voltage
noise than the much more expensive OPA827."<o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>I don't know if this was known before, but anyway great to have the
same brilliant chip for a fraction of the price... and isn't it a great
attitude about quality product sales? :-)<o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>Regarding the inputs, which they don't mention being FET in the
OPA1678 datasheet:<o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>"We received your feedback on the OPA1678 datasheet. With
regards to mentioning the input device type, the OPA1678 is fabricated on a
CMOS process, so yes the device type is indeed a FET (MOSFET). This is also
shown in the simplified diagram of the internal architecture on the first page.<br>
Calling it a “FET” input sometimes raises confusion between whether or not the
devices is JFET or CMOS and I wanted to avoid that when I wrote the OPA1678
datasheet."<o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>/mr<o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB><br>
<br>
On 4 June 2017 at 17:39, Tim Ressel <</span><a
href="mailto:timr@circuitabbey.com" target="_blank"><span lang=EN-GB>timr@circuitabbey.com</span></a><span
lang=EN-GB>> wrote:<br>
><br>
> I started out with the LM4562. Very nice, but as you say, high cabbage
factor. Then I went to the LME49723. Noise is higher but amp is cheaper. If you
really want to break the bank, go with the AD797. Super low noise, super high
price.<br>
><br>
> --timbo<br>
><br>
><br>
> On 6/4/2017 2:29 AM, John P Shea wrote:<br>
><br>
> 4x the price:<br>
><br>
> </span><a href="http://www.ti.com/lit/ds/symlink/lm4562.pdf"
target="_blank"><span lang=EN-GB>http://www.ti.com/lit/ds/symlink/lm4562.pdf</span></a><span
lang=EN-GB><br>
><br>
> DIP & SOIC<br>
><br>
> Regards,<br>
> JPS<br>
><br>
> On Sun, 4 Jun 2017 at 12:21 pm, Tim Ressel <</span><a
href="mailto:timr@circuitabbey.com" target="_blank"><span lang=EN-GB>timr@circuitabbey.com</span></a><span
lang=EN-GB>> wrote:<br>
>><br>
>> It seems to be a popular amp. Mouser got 2500 of the SOICs in and blew<br>
>> through them in days. They have 7K on order. I think they will become
my<br>
>> go-to amp for audio stuff. I'd write TI and ask for the QFN package.<br>
>><br>
>> --tim<br>
>><br>
>><br>
>> On 5/24/2017 10:09 AM, </span><a href="mailto:paula@synth.net"
target="_blank"><span lang=EN-GB>paula@synth.net</span></a><span lang=EN-GB>
wrote:<br>
>> > Tim,<br>
>> ><br>
>> > hey that's neat, though I feel the reverse, s shame it's
not in a<br>
>> > smaller 3x3 QFN package. The VSSOP is close though.<br>
>> ><br>
>> > Thanks for the heads up :)<br>
>> ><br>
>> > Paula<br>
>> ><br>
>> ><br>
>> > On 2017-05-23 21:30, Tim Ressel wrote:<br>
>> >> Hey,<br>
>> >><br>
>> >> Writing to say the OPA1678 from TI is a pretty nice little
amp. Low<br>
>> >> noise, low distortion, low bias current, low cost. Is a dual;
OPA1679<br>
>> >> is a quad. SMT only, sad to say, but that be the times we
live in.<br>
>> >><br>
>> >> </span><a href="http://www.ti.com/lit/ds/symlink/opa1678.pdf"
target="_blank"><span lang=EN-GB>http://www.ti.com/lit/ds/symlink/opa1678.pdf</span></a><span
lang=EN-GB><br>
>> > _______________________________________________<br>
>> > Synth-diy mailing list<br>
>> > </span><a href="mailto:Synth-diy@synth-diy.org" target="_blank"><span
lang=EN-GB>Synth-diy@synth-diy.org</span></a><span lang=EN-GB><br>
>> > </span><a href="http://synth-diy.org/mailman/listinfo/synth-diy"
target="_blank"><span lang=EN-GB>http://synth-diy.org/mailman/listinfo/synth-diy</span></a><span
lang=EN-GB><br>
>> ><br>
>><br>
>> --<br>
>> --Tim Ressel<br>
>> Circuit Abbey<br>
>> </span><a href="mailto:timr@circuitabbey.com" target="_blank"><span
lang=EN-GB>timr@circuitabbey.com</span></a><span lang=EN-GB><br>
>><br>
>> _______________________________________________<br>
>> Synth-diy mailing list<br>
>> </span><a href="mailto:Synth-diy@synth-diy.org" target="_blank"><span
lang=EN-GB>Synth-diy@synth-diy.org</span></a><span lang=EN-GB><br>
>> </span><a href="http://synth-diy.org/mailman/listinfo/synth-diy"
target="_blank"><span lang=EN-GB>http://synth-diy.org/mailman/listinfo/synth-diy</span></a><span
lang=EN-GB><br>
><br>
><br>
><br>
> _______________________________________________<br>
> Synth-diy mailing list<br>
> </span><a href="mailto:Synth-diy@synth-diy.org" target="_blank"><span
lang=EN-GB>Synth-diy@synth-diy.org</span></a><span lang=EN-GB><br>
> </span><a href="http://synth-diy.org/mailman/listinfo/synth-diy"
target="_blank"><span lang=EN-GB>http://synth-diy.org/mailman/listinfo/synth-diy</span></a><span
lang=EN-GB><br>
><br>
><br>
> -- <br>
> --Tim Ressel<br>
> Circuit Abbey<br>
> </span><a href="mailto:timr@circuitabbey.com" target="_blank"><span
lang=EN-GB>timr@circuitabbey.com</span></a><span lang=EN-GB><br>
><br>
><br>
> _______________________________________________<br>
> Synth-diy mailing list<br>
> </span><a href="mailto:Synth-diy@synth-diy.org" target="_blank"><span
lang=EN-GB>Synth-diy@synth-diy.org</span></a><span lang=EN-GB><br>
> </span><a href="http://synth-diy.org/mailman/listinfo/synth-diy"
target="_blank"><span lang=EN-GB>http://synth-diy.org/mailman/listinfo/synth-diy</span></a><span
lang=EN-GB><br>
><o:p></o:p></span></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
lang=EN-GB>_______________________________________________ Synth-diy mailing
list </span><a href="mailto:Synth-diy@synth-diy.org" target="_blank"><span
lang=EN-GB>Synth-diy@synth-diy.org</span></a><span lang=EN-GB> </span><a
href="http://synth-diy.org/mailman/listinfo/synth-diy" target="_blank"><span
lang=EN-GB>http://synth-diy.org/mailman/listinfo/synth-diy</span></a><span
lang=EN-GB> <o:p></o:p></span></p>
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<p class=MsoNormal><span lang=EN-GB><o:p> </o:p></span></p>
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