[sdiy] Happenin' new opamp

[Mattias Rickardsson]

No, but he said he was OK with me sharing it, so now it's more like a
charming sales point for nerdy engineers. If you'd see any.  O:-)

/mr


On 19 April 2018 at 15:35, Roman Sowa <modular at go2.pl> wrote:

> Great news!
> Thanks for sharring.
> Guess the "little secret" is not secret anymore.
>
> Roman
>
> W dniu 2018-04-19 o 15:10, Mattias Rickardsson pisze:
>
>> 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 <mailto:
>> 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 <
>> 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
>> <mailto: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 <mailto: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 <
>> http://www.ti.com/lit/ds/symlink/opa1678.pdf>
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>>  >>
>>  >> --
>>  >> --Tim Ressel
>>  >> Circuit Abbey
>>  >> timr at circuitabbey.com <mailto:timr at circuitabbey.com>
>>  >>
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>>  > --
>>  > --Tim Ressel
>>  > Circuit Abbey
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