An OTA-C filter in SOI CMOS for UWB application

A 4^th-order Butterworth OTA-C lowpass filter based on voltage mode multiple loop feedback (MLF) inverse follow the leader feedback (IFLF) structure is implemented to support both MB-OFDM UWB and low data rate IR-UWB applications. The filter is implemented using a fully-differential linear operational transconductance amplifier (OTA) in 0.25μm SOI CMOS process. A positive feedback topology is used to form a negative resistance load; in such a way, the DC gain of OTA is enhanced. Moreover, the linearity is improved by means of active biasing. AWR simulations in a 0.25μm SOI CMOS process with 2.5V power supply have shown that the cut-off frequency of the filter ranges from 120MHz to 280MHz and dynamic range is about 54dB. The total power consumption is only 32mW at 250MHz cut-off frequency.