Design Of Low Power Complex Filter

As one crucial part of receiver,complex filter achieves selection of desired signal and rejection of image interfere.Its performance,such as power consumption and frequency response,plays one important role in the whole receiver.Enhancing the current efficiency and reducing the power supply are two primary approaches to realize the low power complex filter,which attracts a lot of researches.The system block is obtained by the derivation of basic transfer function.Based on the obtained system block,one low power complex filter is designed which implements two poles with one opam.Thus,less active components are required and current efficiency is enhanced.An optimized topology is found through the derivation and analysis of some related design equations.In order to reducing the power consumption further,one amplifier based on the idea of master-slave is employed as the main cell,which is suitable for low voltage operation because of constant current characteristic in the linear region through feedback.In this method,the headroom from power to ground has been saved with proper CMRR and the goal of low power is achieved with the above two measurements.In order to simplify the complex filter system and saving power,the traditional manual calibration is employed in this design.The complex filter with frequency calibration has been taped out by MPW in TSMC 0.13?m RFCMOS technology and the area is 0.24 mm2.The measurements show that the 4th-order complex filter consumes 0.5mA with 0.7V supply.Its bandwidth is 0.9MHz with gain=8.1dB and fc=1.68MHz.The measured inside IIP3 and IRR is-9.41 dBm and 18.33dB,respectively.