An Improved OTA for a 2nd Order Gm-C Low Pass Filter
A low power Gm-C low pass filter used in a direct conversion receiver for mobile applications is presented. The proposed Operational Transconductance Amplifier (OTA) consists of a class AB pseudo-differential input stage and a high linearity current multiplier with switched capacitor common mode feedback. Simulation results prove that, due to the class AB operation of the proposed OTA, a very high transconductance value of 540 S is obtained. A second order Butterworth low pass filter is implemented with this transconductance amplifier using TSMC 0.35?m CMOS technology in H-spice, Synopsis tool.