Design and Implementation of 2nd Order Gm-C IF Tuning Filter Operating at 900 MHz and 88–108 MHz Wireless System for Multi Standard Receiver

Abstract

This paper deals with design and optimization of folded cascode OTA-C filter, which works for frequencies that lead to a base band circuit design for RF application, is based on transistor sizing methodology and Simulation results are performed using SPICE software and BSIM3V3 model for CMOS 0.18 μm process, show that the designed folded cascode OTA has a 52 dB DC gain and provides a Unit gain bandwidth of around 400 MHz. Design of CMOS Gm-C 2nd order Biquad Filter implementation using OTA, operating at center frequency 70 and 10.6 MHz. The filter can be operated at center frequency of 70 MHz under 1.8 V power supply and is suitable for intermediate frequency (IF) range in most of the wireless systems operating at 900 MHz GSM and at
88–108 MHz FM.

Keywords: Folded cascode OTA, gm/ID methodology, active filters, S-parameter, smith chart, OTA-C filters, GSM, FM