A high frequency current mode ladder filter using multiple output lossless integrator

This paper describes a current mode integrator and filter. The circuit can operate at high cutoff frequency and has low input impedance. The design of current mode integrator is based on a low input impedance current mirror with grounded capacitors. The integrator provides a building block for using in active filter circuits based on the doubly terminated LC ladder filter prototype. A 5^th order low pass active ladder filter using the integrator is designed as an example and simulated by H-SPICE using the standard 0.5 mum CMOS technology. The designed cutoff frequency of the filter is 200 MHz and can be electronically tuned from 90-250 MHz by varying the DC bias current. The input impedance of the filter is low (11 ohm). The power dissipation is 1.2 mW/pole and is very practical when operated with a voltage supply of 1.5 V.