Measured hyperbolic-sine (sinh) CMOS results: A high-order 10Â Hz-1Â kHz notch filter for 50/60Â Hz noise

This paper presents proof-of-concept measured results from CMOS hyperbolic-sine (sinh) filters fabricated in a commercially available 0.35 µm CMOS technology. Results from two chips are reported: a practical sinh integrator and a high order (8th) notch filter dedicated to 50/60 Hz noise rejection and synthesized by means of the proposed integrator. Linearity, frequency and noise measurements are reported. The notch frequency of the 8th order filter can be tuned over almost two decades. Its attenuation exceeds 70 dB for the target frequency range of 20-60 Hz and its dynamic range (for THD<4%) amounts to 89 dB while consuming 8 µW from a 2 V power supply level. For an increased power consumption of 74 µW its dynamic range (for THD<4%) exceeds 100 dB.