A low-power reconfigurable analog filter for UMTS/WLAN receivers

A low-power analog filterable to be reconfigured in order to be used in UNITS and WLAN applications is reported. The 4th order low-pass continuous-time filter is going to be included in the receiver path of a reconfigurable terminal. The filter is made up by the cascade of two Active-G(m)-RC low-pass biquadratic cells. The unity-gain-bandwidth of the opamps embedded in the Active-G(m)-RC cells is comparable to the filter cut-off frequency. Thus, the power consumption of the opamp can be strongly reduced. In addition, the filter can be programmed in order to process UNITS and WLAN signals, while a little area overhead is required since the filter can share capacitors as well as opamps in both operations modes. The cut-off frequency deviation due to the technological spread, aging and temperature variation is adjusted by using a tuning circuit. The full device in a 0.13 mu m CMOS technology occupies a 2.8 mm(2) area.