quad OP-amps

[CGS2510.SEP.STUDENT.UCA at CUB.UCA.EDU]

> is there any major difference in the quality of quad OP-amps as compared
> to dual or even single packages?  I am just curious why anyone would use
> a TL081 type OP-amp when they could sqeeze so much more circuit per inch
> with say a TL084. 

There is a difference between the TL081 and the TL082/TL084.  The 81 
brings the pins used for external compensation out as do most op amps 
so they are a bit more versatile in extreme circumstances.  Most of 
the time you leave them unconnected.  The 82 and 84 are the same with 
no external compensation.  I don't usually like quad op amps and 
almost never use them despite there being cheaper per op amp and you 
can make tighter pc boards with them.  One argument against them is 
crosstalk and the power supply  coupling signal between them.  82's 
are more appealing to me because it leads to more related signal on 
the same IC and adds better power supply decupling (more) than do the 
quads.  You tend to also not have as much wasted op amp with the 
duals.