[sdiy] TL072??

[Dave Manley]

On June 10, 2014 10:30:23 PM PDT, Dave Manley <dlmanley at sonic.net> wrote:
>
>
>On June 10, 2014 9:03:35 PM PDT, Tim Ressel <timr at circuitabbey.com>
>wrote:
>>Hi,
>>
>>Someone please explain to me the difference between the TL072 and the
>>TL082. I keep hearing about its low noise, but according to the
>>datasheets the noise is identical, as is the input offset current. The
>>input bias current is actually higher on the TL072.  
>>
>>I don't get it.
>>
>>
>>
>>Tim Ressel
>>Circuit Abbey
>>503-750-9331
>>timr at circuitabbey.com 
>
>In today's manufacturing process there really is no difference. 
>According to one site in 1977 the TI  noise specs were 47nV vs 18nV for
>'81 vs '71.  I don't feel like digging up my ancient data books, so
>can't confirm, but it makes sense. Test the same die and bin the better
>parts separately, and charge more for them, where 'better' could be
>speed, power, noise, offset, or some other parameter. It could also be
>that in those days they slightly tweaked the process recipe to optimize
>the same mask set for different performance, and sold them under
>different part numbers.
>
>-Dave
>

Walter Jung's 1974 IC Op-amp Cookbook doesn't have the TL series yet,  but the 1980 edition states:

"In October of 1976, Texas Instruments introduced the TL084..."

And then later, "Texas Instruments further improved and broadened their line of FET devices with the introduction of the TL071 series in July of 1977. ...similar to the TL081 series, but feature lower noise and distortion for ac uses."

-Dave