Amplifier with very low input referrd noise (less than 2nV)?

[yolande_yj]

lsk389 amplifiwer

How to design an low noise amplifier (BW<1K) that has very low input refer noise (or very low offset) ? I think Autozero and Chopping is not good enough. If I can use offchip JFET like LSK (**broken link removed**), how to do the following design?
Also, I found an ultra low noise OpAmp from TI (OPA228: http://focus.ti.com/docs/prod/folders/print/opa228.html), the input referred noise is only 3nV/srHz, how can they do that?

 

[pupkin]

lsk389 + noise

Look a Datasheet on MAX4106 (0.95 nv/sqrtHZ, 2,8 pa/sqrtHZ) and read a book Motchenbacher C.D. Connelly J.A."Low-noise electronic system design ".

Best regards....

 

[eldo]

As I know, AD797 is also a very low-noise opamp. If you use CMOS, it is difficult to reach this spec. I guess they have special technologies to support the low-noise design.

 

[cinvo]

Re: Amplifier with very low input referrd noise (less than 2

chopper stablized and multipath feedforward compensation