Design of a CMOS fully-differential continuous-time tenth-order filter based on IFLF topology

The design of a CMOS fully-differential continuous time tenth-order lowpass filter with equiripple group delay based on the inverse-follow-the-leader feedback (IFLF) topology is discussed. A very-high-frequency operational transconductance amplifier (OTA) with negative resistive load (NRL) is used as a basic building block. Simulation results show the group delay sensitivity of IFLF circuits is very large. Measurement results verify the design method of IFLF filters, and also their sensitivity problems. Solutions are proposed.