A CMOS inverse Chebyshev channel selection filter for extravehicular activity (EVA) radio receivers

This paper presents an inverse Chebyshev filter for channel selection in the baseband section of an extravehicular activity (EVA) fully integrated radio receiver. The filter is synthesized from a 4^th order doubly-terminated LC ladder prototype using a leapfrog structure in order to minimize the use of active components. The cutoff frequency of the filter is digitally controlled for different channel bandwidths through a binary weighted capacitor bank that allows tuning from 1.1 MHz to 2.28 MHz. The derivation of the filter specifications from the system level parameters of the EVA radio receiver is presented. Also, the impact of the channel selection filter in the overall receiver performance is discussed. The circuit is implemented using the IBM 0.18 μm standard process and post-layout simulations show a pass-band gain of -0.07 dB, an IIP3 of 38 dBm, adjacent channel rejection better than 50 dB and a noise figure of 30.2 dB. The filter operates from a 1.8 V power supply consuming 4.03 mA.