A 40 µ w, 75dB dynamic range, 70kHz bandwidth biquad filter based on complementary MOS transconductors

This paper presents a low-power gm-C filter using a topology with alternated NMOS and PMOS transconductors. A dedicated bias circuit matches the complementary transconductances which are based on transistors operating in the triode region. This principle was verified by implementing a low-pass biquad filter in a 0.25µm CMOS digital technology. Measurements show that a dynamic range of 75dB can be achieved with only 3.5pF of total capacitance and at 2.5V supply voltage.