Exponential-enhanced characteristic of MOS transistors and its application to log-domain circuits

In this paper we present a fully CMOS-compatible circuit that extends the weak-inversion exponential characteristic of a MOS transistor to seven decades of current. This circuit can be used to implement log-domain or translinear circuits up to the strong inversion region, allowing highly-accurate implementations of translinear loop functions and higher biasing currents (and potentially higher frequency operation) than MOS weak-inversion biased log-domain circuits.