A CMOS 80mW 400MHz seventh-order MLF FLF linear phase filter with gain boost
A 400MHz CMOS seventh-order linear phase gm-C filter based on current-mode (CM) follow-the-leader-feedback (FLF) structure is realized. The filter is implemented using a fully-differential linear operational transconductance amplifier (OTA) based on source degeneration topology. PSpice simulations in a standard TSMC 0.18mum CMOS process and with 2.5V power supply have shown that the cut-off frequency of the filter ranges from 290MHz to 430MHz and dynamic range is about 54dB. The group delay ripple is approximately 6% over the whole tuning range and total power consumption is only 78.7mW at 400MHz cut-off frequency.