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 Butterworth lowpass filter using the proposed cell has been designed in 0.18 ¿m CMOS technology. The active area occupied by the filter with test buffer is only 200×170 ¿m. The presented filter consumes low power 201 ¿W and achieves a 52.1dB dynamic range.