A current-mode biquad filter for Zigbee applications using 45nm ±0.75V CMOS CDTA

This paper proposes a current-mode bi-quad filter based on 45nm CMOS technology which is in accordance with the modern day fabrication process. The proposed filter is designed employing one MO-CDTA circuit, one current differencing circuit, two grounded capacitors and two resistors. The circuit operates at supply voltages of ±0.75V. It is a Single-Input Multiple-Output (SIMO) topology which realizes low pass (LP), band pass (BP), high pass (HP) and band stop (BS) outputs simultaneously. The CDTA used has lower transistor count, high precision, low biasing voltage, low input impedance, high output impedance, low power consumption and stable operation at high frequency. The characteristics of CDTA and bi-quad filter are simulated with computer SPICE simulation software using 45nm PTM CMOS model process and the results are in close correspondence with the theory. As an application, band-pass filter designed at three Zigbee frequencies viz. 784 MHz, 868 MHz and 915 MHz are also included.