[sdiy] Op amp notes

[Ian Fritz]

Hey listers --

While ordering some replacement parts I noticed that Burr-Brown (TI) is no 
longer making my favorite general-purpose high-performance op amps, the 
OPA132, 2132 and 4132, in DIP packages.  They are still available in 
SOIC.  Poking around a bit, I noticed that the OPA134, 2134 and 4134 
appears to be a practically identical series, except fully speced (and 
marketed) for audio applications. They are also a fair bit less 
expensive.  So anyone looking at my designs using these chips should 
consider substituting the x134 for the x132

I also noticed for the first time (DOH) the TL051,2,4 series.  For anyone 
as asleep at the wheel as I am, these are improved replacements for the 
TL07x and TL08x series.  Their performance is quite impressive for their 
price: Typical offset of 0.35 mV, input bias of 30 pA and slew rates of 
about 20 V/usec. For people making do with 07x's in critical applications, 
this might be a worthwhile upgrade.

   Ian