A high performance charge sampling baseband filter for multimode receiver

This thesis presents a high performance charge sampling baseband filter for multimode receiver dedicated to Bluetooth and UMTS implemented with proposed new high linear transconductor with 3rd order distortion cancellation. The proposed transconductor takes advantage of the parallel operation of triode transistor and saturation transistor and cross coupled connection for the fully differential topology. Further advancement is being implemented in proposed design to achieve third order distortion cancellation using master-slave structure. This design is implemented at transistor-level using TSMC 0.18microm CMOS technology which exhibits a peak SNDR of 69.4dB at 81MHz signal frequency with 4.38mW power consumption. Also the post-layout simulation gives SNDR of 66.8dB considering the effect of parasitic capacitances. The influence of the transconductor linearity on the performance of the charge sampling circuit is investigated to justify the necessity of highly linear transconductor. Finally, the baseband filter based on charge sampling circuit using the proposed transconductor is proposed which is reconfigurable for different communication standards such as: Bluetooth (1.1 MHz) and UMTS (2.3MHz) by changing sampling frequency. For both standards the proposed filter exhibits almost same amount of in-band input referred IP3 +22 dBm.