Silicon germanium (SiGe) opamps

[splin]

I was just looking at the ADA4805 datasheet and was a bit surprised to read:

The Analog Devices silicon germanium (SiGe) bipolar process makes it possible to achieve a low noise of 5.9 nV/?Hz for the ADA4805-1/ADA4805-2. This noise is much improved compared to similar low power amplifiers with a supply current in the range of hundreds of microamperes.

I wasn't aware of this process. Can we expect improved, ie. quieter, versions of other popular bipolar opamps to appear gradually or are the noise advantages only applicable to low power applications?

Is it already widely used? What are the disadvantages?

Does anyone know how to search pdf files other than opening them individually in a viewer as grep doesn't work?

[moffy]

SiGe is as far as I know a high ft bipolar process. As is usual with bipolar you can trade off speed vs power. It is also more expensive so I would only expect to see it used in higher end parts. But thanks for the info, had no idea that commercially available SiGe opamps were avaliable.

[Marco]

Fiber communication and mm wave ASICs have used it (and InP) for a long time, but it seems to be migrating into lower margin products now.

There were already quite a few comparators using it, but I hadn't seen any opamps either. Quick google shows TI used for opamps for quite a while already though, in the LMH6629 for instance.