Hmmm, not aware of any GOOD ones.
I've seen and tried several but they all have serious flaws.
Quality, quality and quality.
It really depends what you want.
If you want just an image that is not really an image, PDF to CAD is slightly passable.
I suggest to have a look at AutoCAD Raster Design.
@rjdjr63 as kevynm has said, Scan2CAD will take care of Tiff to AutoCAD file conversions for you.
You can download Scan2CAD for free and give it a try yourself, It's a fully working demo with no functions locked.
If you have any questions during your free trial please feel free to contact us at www.scan2cad.com/support and the support team would be happy to help
@kevynm many thanks for your recomendation.
Luke - Scan2CAD Support