[sdiy] Happenin' new opamp

[Mattias Rickardsson]

Share it if you wish! John Caldwell said:

"Feel free to leak the secret, if it means more people buy my part then I’m
happy :-) "

/mr

On 19 April 2018 at 15:44, Rob Spencer <rob at gmsn.co.uk> wrote:

> Good to know! Would you mind I if share this on the GMSN forum?
>
>
>
> Rob Spencer
>
> 07590 267835
>
> [image:
> /Users/Rob/Library/Containers/com.microsoft.Outlook/Data/Library/Caches/Signatures/signature_768746585]
>
>
>
> *From: *Synth-diy <synth-diy-bounces at synth-diy.org> on behalf of Mattias
> Rickardsson <mr at analogue.org>
> *Date: *Thursday, 19 April 2018 at 14:16
> *To: *Tim Ressel <timr at circuitabbey.com>
> *Cc: *Synth DIY <synth-diy at synth-diy.org>
> *Subject: *Re: [sdiy] Happenin' new opamp
>
>
>
> I'm throwing in some news (for me at least) about the fairly new
> OPA1678/79 low-noise rail-to-rail FET-input 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 John Caldwell. He writes:
>
>
>
> "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.
> 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."
>
>
>
> 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? :-)
>
>
>
> Regarding the inputs, which they don't mention being FET in the OPA1678
> datasheet:
>
>
>
> "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.
> 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."
>
>
>
> /mr
>
>
>
> On 4 June 2017 at 17:39, Tim Ressel <timr at circuitabbey.com> wrote:
> >
> > 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.
> >
> > --timbo
> >
> >
> > On 6/4/2017 2:29 AM, John P Shea wrote:
> >
> > 4x the price:
> >
> > http://www.ti.com/lit/ds/symlink/lm4562.pdf
> >
> > DIP & SOIC
> >
> > Regards,
> > JPS
> >
> > On Sun, 4 Jun 2017 at 12:21 pm, Tim Ressel <timr at circuitabbey.com>
> wrote:
> >>
> >> It seems to be a popular amp. Mouser got 2500 of the SOICs in and blew
> >> through them in days. They have 7K on order. I think they will become my
> >> go-to amp for audio stuff. I'd write TI and ask for the QFN package.
> >>
> >> --tim
> >>
> >>
> >> On 5/24/2017 10:09 AM, paula at synth.net wrote:
> >> > Tim,
> >> >
> >> >  hey that's neat, though I feel the reverse, s shame it's not in a
> >> > smaller 3x3 QFN package. The VSSOP is close though.
> >> >
> >> >  Thanks for the heads up :)
> >> >
> >> > Paula
> >> >
> >> >
> >> > On 2017-05-23 21:30, Tim Ressel wrote:
> >> >> Hey,
> >> >>
> >> >> Writing to say the OPA1678 from TI is a pretty nice little amp. Low
> >> >> noise, low distortion, low bias current, low cost. Is a dual; OPA1679
> >> >> is a quad. SMT only, sad to say, but that be the times we live in.
> >> >>
> >> >> http://www.ti.com/lit/ds/symlink/opa1678.pdf
> >> > _______________________________________________
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> >> >
> >>
> >> --
> >> --Tim Ressel
> >> Circuit Abbey
> >> timr at circuitabbey.com
> >>
> >> _______________________________________________
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> >
> >
> >
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> >
> >
> > --
> > --Tim Ressel
> > Circuit Abbey
> > timr at circuitabbey.com
> >
> >
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