A Low Voltage, Low Power Cmos Fifth Order Elliptic Low Pass Gm-c Filter for Direct Conversion Receiver

This paper presents the fifth-order elliptic low-pass Gm-C filter (LPF) used in direct conversion receivers for Zigbee applications. The proposed LPF is designed based on rail-to-rail differential input voltage transconductance amplifier (OTA). The high linearity OTA is designed by combining two previous linearization techniques in [3] and [4]. The 5-order elliptic low-pass GmC filter has a tuning range from 0.8 to 1.2 MHz and provides out-of-band attenuation of –50 dB. This filter has –65 dB of total harmonic distortion (THD) with 0.625 Vpp at 800 KHz sinusoidal input signal. The proposed LPF and operates at a supply voltage of 1.25 V, and dissipates 250 μW in 0.25 μm CMOS technology.