Gate Diffusion Input (GDI) is a lowest power design technique which offers improved logic swing
and less static power dissipation.
The logic swing is [DELTA]V = [V.sub.OH] - [V.sub.OL] = [I.sub.B][R.sub.D].
In almost all designs, the logic swing of DRMCML circuits is taken as [DELTA]V < [V.sub.th], this is because the NMOS transistor [N.sub.1] can operate at saturation region.
The logic swing
of a digital technology is imposed by the active device and logic gate structure.
To achieve higher-speed performance while keeping the power dissipation as low as possible, CML stages are currently used with a logic swing
as low as 400 mV and even 200 mV locally.