A Gm-C Biquad Programmable Band Pass Filter for Wireless Applications

A biquad Gm-C programmable band-pass filter has been designed for wireless applications. The filter is designed by cascading four biquad stages with each stage consisting of a parallel combination of an active resistor, capacitor and active inductor. Nauta trans-conductor stage is used as a trans-conductance block which is also used to realize the active resistor. Karsilayan active inductors are used in place of gyrator-C active inductors to reduce the power consumption. A new tuning technique is devised to digitally control the centre frequency of the filter ranging from 910 MHz to 2.09 GHz with a pass-band gain of ~40dB. In the proposed tuning scheme, the Karsilayan active inductor has been varied instead of the capacitor. The power consumption of the filter is relatively lower (close to 56 mW) as compared to other high frequency filters operating in the same frequency range. The design has been carried out in 180-nm standard CMOS technology.