The many versions of the NE5532 and I'm confused!

G'day all, last night I was about to place an online order for some NE5532 op amps from my usual online supplier but I find that they list several versions of the NE5532 ((NE5532AP, NE5532P and probably others!)

The specs all look the same but there is an appreciable difference in price between these two items! Can anybody tell me what the differences are? I presume it is a 'noise' difference, or is it? I am after the 'quietist' version. It is very confusing! Regards, Felix.

 

Felix,

The DIP package you are looking for is the NE5532AP.
The spec is called "Noise Figure" and it is the ambient thermal noise present in the amplifier which will be added to the noise generated by your circuit including the input signal. I'm really not sure there is a "quietest version" of that amp they are just different packages. It might be time to look at something more current and suited for an instrumentation application. You may pay more but cheap is not always the best deal.