A CMOS fifth-order 400MHz current-mode LF linear phase filter for hard disk read channels
A 400 MHz CMOS fifth-order linear phase gm-c filter based on current-mode (CM) leapfrog (LF) 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 0.18 mum CMOS process and with 2.5 V power supply have shown that the cut-off frequency of the filter ranges from 330 MHz to 450 MHz and dynamic range is about 64 dB. The group delay is approximately 4% over the whole tuning range and total power consumption is only 190 mW at 400 MHz cut-off frequency.