[sdiy] Difference between TL07x and TL08x OpAmps?

[Bob Weigel]

Hehe..uhh no.  The TL082 was generally available for a lower 
price...hence it's use in S+H buffers and so on where specs aren't all 
that important except for bias current which as long as it's anything 
reasonable even for a JFET amp is ok.  In those days 074's always cost 
more and I seemed to recall...that they had better offset AND noise 
specs....and also bias maybe...looking at the spec sheets, that seems to 
bear true for the "C" version at least where offset current is given a 5 
to 200pA range and 100pA is the 25ºC max for the 074.  The bias at 200pA 
max at 25ºC for the 074 compared to the same for 084 but at higher temps 
the 084 appears will drift higher though their way of specifying the 
limits seems a little ambiguous on the 074's and I don't have time to 
care.  Basically I use an 074 if I need tighter specs in those two areas 
though ..the noise being 15mV instead of 18mV on the 084.   But the 
devices cost enough more and for most applications it just doesn't 
matter so manufacturers naturally chose the sloppier chip. -Bob

Seb Francis wrote:

> Hi,
>
> Something I've wondered for a long time is why would anyone want to 
> use TL08x op amps over TL07x?  I've compared the datasheets for the 
> TL072 and TL082 and can find no advantage in using a TL082 for 
> anything.  The price seems pretty much the same for these 2 chips, so 
> why would anyone use a TL082 over a TL072?
>
> These are the only differences between the 2 datasheets ..
>
> TL072 has the followed extra features listed:
> LOW NOISE en = 15nV//Hz (typ)
> LOW HARMONIC DISTORTION : 0.01%(typ)
>
> TL082 has a graph of:
> COMMON MODE REJECTION RATIO
> VERSUS FREE AIR TEMPERATURE
> (this graph is missing from the TL072 datasheet)
>
>
> Because I see the TL08x used so often in schematics, I'm just 
> wondering if I'm missing some secret advantage of the TL08x in certain 
> applications?
>
> Seb
>
>
>
>