Hi,
Let me give you a few pointers.
hacksgen wrote on May 11th, 2011, 4:48am:... As I understand the native devices have lowest threshold close to zero, better matching and also low noise like flicker due to low doping.
Is that what your foundry's data says?
hacksgen wrote on May 11th, 2011, 6:56am:...Usually there is no need of additional mask in creating native transistors since it is formed directly on the substrate. (I quote this from a IEEE paper that I found).
Once upon the time... Nowadays they get their own implantation to set the threshold voltage to the desired value near zero.
Quote:Why is it that then not many designs use them for design of analog circuits like opamps...
Quote: Even if an additional step is needed this should only increase the fabrication costs which I am not concerned with here. I am more interested in its use for building analog blocks assuming costs are not a factor.
Usually, they are only used if they are really needed because for most designers (and their bosses) costs are
the factor. And what kind of circuits are built in 65/90 nm? Purely analog or mixed-signal circuits with a lot of digital content?
Quote:Matching relates to how the transistors are uniform in there properties and I think the uniform doping of the substrate allows only small variations between transistor parameters like in case of a curent mirror.
That's not Alexandar's point. Think about the operating point of the transistors in the current mirror. And don't forget the Vth,native implantation.
Quote:I dont understand what you mean by modelling. Do you mean the model parameters provided by the foundry?
Which models do you think the foundries focus on? Those that are used in millions on every circuit or those only a few designs ever use? On which devices do they have the most data?
B O E