I am interested in using the AD8139 as an RF-switch driver since it's supposed to get <11ns switching speeds. The design is detailed here: www.edn.com/contents/images/10605di.pdf
I am trying to get the swing as close to 0V and -5V as possible to optimize performance in some high speed RF switches. The AD8137 spice model works well for me in comparison to its datasheet, but the AD8139 model can't seem to output any voltage lower than -4V with Vee = - 5V. I believe the AD8139 will be the better option for me as I do not require low power, would benefit by the better rail-to-rail specs, and the speed.
Is this simply an error with the spice model or am I using it wrong? The AD Diff-Amp Calculator shows the rail to be much closer to -5V as advertised in the datasheet. I am using the subcircuit model in LTspice.
From your schematic and your data plot, I don't see a saturation at -4V.
How are you bringing the total voltage down? increase the gain? Lower Vocm?
I would say the AD8139 is a better option then the AD8137 if power is not important.