Design of a fully differential current mode operational amplifier with improved input-output impedances and its filter applications


Altun M. , KUNTMAN H.

AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS, cilt.62, ss.239-244, 2008 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 62 Konu: 3
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1016/j.aeue.2007.03.020
  • Dergi Adı: AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
  • Sayfa Sayıları: ss.239-244

Özet

In this paper, a CMOS implementation of a fully differential current-mode operational amplifier (COA) is presented. To achieve very low input resistance, a new technique based on a positive feedback is used in the input transimpedance stage. Additionally, traditional current output stage (Arbel Goldminz output stage) with improved output resistance is selected as a transconductance stage. Results of simulations exhibit 96 dB DC gain, nearly 120 Omega input, 30 M Omega output resistances and a gain-bandwidth product exceeding 90 MHz. The proposed COA is operated under +/- 1.5 V voltage supplies and designed with 0.35-mu m CMOS process. Furthermore, COA-based fourth-order band-pass (BP) filter consisting of Butterworth low-pass (LP) and high-pass (HP) filters is realized as an application example. SPICE simulation results are included to verify correctness of the designs. (c) 2007 Elsevier GmbH. All rights reserved.