Continuous time analog filters design in ultra-deep-sub-1µm CMOS technologies

Analog filters are widely used in several kinds of integrated mixed-signal systems, since they are intrinsically needed for in-band signal selection, out-of-band noise rejection and anti-aliasing for the A-to-D (D-to-A) conversion. CMOS technological scaling down has already entered in nm-range scenario, leading to severe degradation of some of the most important MOS device performance for analog design. Among them, lower V_DD(V_TH ratio (supply voltage and threshold voltage, respectively), higher power consumption, and transistor intrinsic gain decreasing. On the other side the increasing MOS transistor transconductance (g_m) and transition frequency (f_T) enables tens of GHz applications, which take advantage of cheaper and smart CMOS processes. Specific continuous-time analog filters will be presented in this paper, with the aim to introduce novel circuital topologies or optimizations and techniques suitable to mitigate the severe issues present in sub-90nm C MOS technological nodes, and at the same time to exploit the opportunity of higher technological scaling-down.