A new 5th-order differential type class-AB log-domain elliptic lowpass filter for video frequency applications

Kircay A., ÇAM U.

ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING, vol.60, no.3, pp.221-229, 2009 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 60 Issue: 3
  • Publication Date: 2009
  • Doi Number: 10.1007/s10470-009-9292-z
  • Journal Name: ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.221-229
  • Keywords: Log-domain filters, Current-mode circuits, Differential type class-AB circuits, State-space synthesis, Elliptic filters, Video frequency, CONTINUOUS-TIME FILTER, INTEGRATOR
  • Dokuz Eylül University Affiliated: Yes

Abstract

This paper proposes a new current-mode 5th-order differential type class-AB log-domain elliptic lowpass filter for video frequency applications. The design is based on the state-space synthesis method. The proposed filter has 5.75 MHz cut-off frequency with maximum 0.177 dB passband ripple and attenuation greater than 40 dB at 7.88 MHz. Only BJTs and grounded capacitors were used, and operated with single power supply of 2.5 V. Since the parameters of proposed filter are tunable, it is easy to control of cut-off frequency. This adjustment is accomplished by changing external currents. SPICE simulations are given to confirm the theoretical analysis. For this purpose, the filter is simulated by using both idealized BJT models and AT&T CBIC-U2 type transistors.