Design of a low-pass filter for wideband transceiver

In this paper, a channel-select filter for wideband transceiver is designed using Gm-C structure. Schematic and layout of the design are completed in TSMC 0.13μm CMOS process. A transconductance amplifier used in Gm-C filter is investigated in depth. Considering the filter architecture, the transconductance amplifier are designed with source degeneration, common-mode feedback and common-mode feedforward. The transconductance amplifier is used to constitute Gm-C low-pass filter for completing the design of channel selection filter. According to post-layout simulation, the filter can be tuned among 156MHz, 102MHz and 79MHz. Power consumption of the filter is 3. 47mW. Total harmonic distortion is 0.5% at high frequency, 0.3% at medium frequency and 0.7% at low frequency. Stop-band attenuation at 2nd order harmonic is 28. 9dB, 27.2dB and 26. 5dB respectively. Input referred noise is smaller than 71nV/$\sqrt{\mathrm{H}\mathrm{z}}$.