Novel Low‐Power High‐dB Range CMOS Pseudo‐Exponential Cells

In this paper, novel CMOS pseudo‐exponential circuits operating in a class‐AB mode are presented. The pseudo‐exponential approximation employed is based on second order equations. Such terms are derived in a straightforward way from the inherent nonlinear currents of class‐AB transconductors. The cells are appropriate to be integrated in portable equipment due to their compactness and very low power consumption. Measurement results from a fabricated prototype in a 0.5 μm technology reveal a range of 45 dB with errors lower than ±0.5 dB, a power consumption of 100 μW, and an area of 0.01 mm 2 .