Harmonic vs. geometric mean Sinh integrators in weak inversion CMOS

In this paper a novel, practical, low-power, Class-AB companding hyperbolic sine (Sinh) integrator based on the harmonic mean law is presented. MOS transistors operating in their weak inversion region are used for low power and low supply voltage operation. All translinear loops are implemented using single-type devices allowing for fabrication on standard, twin-well CMOS processes. Detailed simulation results from Cadence IC Design Framework and the commercially available AMS 0.35μm process parameters are reported and discussed. The proposed circuit achieves more than 120dB of input dynamic range, and a frequency tunability of over 4 decades with a power consumption of less than 1.5μW. In addition, head-to-head comparison with our previously reported (ISCAS ’07) geometric-mean Sinh integrator is performed in an attempt to shed more light on the potential of this very promising class of current-mode companding filters.