A Low Power CMOS Mixed-Integrator-Based Continuous-Time Filter

a new Mixed-Integrator-Based bi-quad cell is presented. An alternative synthesis mechanism of complex poles is proposed comparing to source-follower-based bi-quad cells which is designed applying positive feedback technique. Using negative feedback technique to combine different integrator, the proposed bi-quad cell synthesizes complex poles for designing continuous-time filter. It exhibits various advantages including compact structure, high gain, no parasitic pole, absence CMFB circuit, and high capability. An example the 4(th)-order Buttenvorth lowpass filter using the proposed cell has been designed in 0.18 mu m CMOS technology. The active area occupied by the filter with test buffer is only 200 x 170 mu m. The presented filter consumes low power 201 mu W and achieves a 52.1dB dynamic range.