Design of active-only highpass and bandpass leapfrog filters using multi-current-output differentiators

This paper presents an alternative approach for realizing active-only current-mode leapfrog ladder filters using a multi-current-output differentiator. A novel multi-output differentiator, which is only composed of internally compensated type operational amplifiers (OA) and operational transconductance amplifiers (OTAs), is first proposed. The proposed design procedures of the active-only current-mode highpass and bandpass leapfrog ladder filters, employing only OTAs and multi-output differentiators without external passive elements, are then presented. A property of this approach is the possibility of tuning the current transfer function by the external controlled transconductances. PSPICE simulation results verifying theoretical predictions are included.