TL071/TL081

[Scott Bernardi]

Same chip with different yields is probably the case with the 07x, 08x, etc. When
I was at PMI, we did a number of tricky things behind the scenes - like take 12
bit DACs that didn't pass the specs and package them as 10 bit DACs. I remember
that we were getting such good yields on the OP27 A and B grade parts that we had
trouble getting enough C grade parts - so we just took the A's and B's and labeled
them as C's.

Grant Richter wrote:

> As far as semi-conductors go. There are only so many die types, and doping
> is still a somewhat uncertain process. A number of different parameters are
> going to have Gaussian (bell curve) distributions around the center target
> point. But you don't want to have to throw away dies outside some
> percentile. You just assign them a different part number with a relaxed
> spec.
>
> In the old days, they would take a batch of transistor die and "test" them
> into part numbers. That is they would check the die test results against
> multiple specs and slap a part number on the ones that passed for that part
> number. So the same die might appear as several part numbers.
>
> I could be wrong, but I believe that's how 2N3905/2N3906 (higher betas are
> 3906) CA3045/CA3046 (higher betas as 3046) and so forth. Basically splitting
> the bell curve and assigning two different part numbers to the upper and
> lower half, and charging more for the better results.
>
> Maybe the 1N400x series are also like that, a 1N4001 is a 1N4002 die that
> tested below 100 volts, so now it's rated at 50 volts but might actually
> have a breakdown voltage between 50 and 90.
>
> I had always assumed the TL07x were the lower half of the bell curve for
> TL08x sorted for noise figure. The noisier die that still pass DC spec are
> labeled 08x and the quieter ones 07x, but otherwise are the same die?
>
> ----------
> >From: Jim Patchell <patchell at silcom.com>
> >To: Tim Curtis <sexsymbol at execpc.com>
> >Cc: AH <analogue at hyperreal.org>, synth-diy at node12b53.a2000.nl
> >Subject: Re: TL071/TL081
> >Date: Thu, Nov 9, 2000, 8:54 AM
> >
>
> >     In my opinion, the two are pretty much interchangeable.  The 07x seriers
> > has a slightly quieter front end, and I believe the output stage is biased a
> > little heavier to give better distortion.  In general, I have used the two
> > interchageably.
> >
> >     -Jim
> >
> > Tim Curtis wrote:
> >
> >> Can anyone really explain to me what the difference is between these two
> >> op-amps?
> >>
> >> One of my MiniMoog Oscillator boards was diagnosed as having a bad
> >> TL081.  I replaced it with a TL071because I have some of those around.
> >> Nada.
> >>
> >> Is this normal?  I was always told that the two were pretty much
> >> interchangeable.
> >>
> >> Or is it just a problem with them in that circuit?
> >>
> >> Tim
> >
> >

--
Scott Bernardi
sbernardi at home.net