A Low Power Low-Pass Fourth-Order Filter for WiMAX/LTE Receiver in CMOS 45nm Technology

Abstract

In this paper, a [Formula: see text]-[Formula: see text] low-pass and low power filter with tunable in-band attenuation for WiMAX/LTE receiver is presented. The fourth-order filter consists of two cascaded biquad stages. The source-follower (SF) stage is used as a key building block in these biquads. In this paper, we have presented a circuit technique to reduce the nonlinearity of the SF stage resulting from unmatched signal swings at the gate and source terminals of the input transistor. The proposed SF stage, is used for design of a linear biquad which is then utilized in a fourth-order Butterworth low-pass filter. The simulation results of the filter for bandwidth of 10 MHz show that the IIP3 of the filter is equal to 8.22[Formula: see text]dBm, in-band noise density is 100[Formula: see text]nV/[Formula: see text]Hz and power consumption is 5.9[Formula: see text]mW. The supply voltage of the filter is equal to 1[Formula: see text]V.