Low power wideband voltage and current mode second-order filters using wideband CMOS transimpedance network

Abstract

A very wideband CMOS transconductor is used to build a wideband transimpedance amplifier, which realizes second order low pass filters having -3 dB bandwidth to 75.6 MHz and band-pass filter with center frequency of 159 MHz using 1 pF with /spl plusmn/1.25 V power supplies. The power dissipations are respectively 0.67 mW and 0.45 mW per pole. Using Miller effect capacitance of MOS transistors, the low pass filter can be tuned from 124 MHz to 233 MHz with slightly increased power dissipation (0.78 mW per pole). An alternate architecture produces a low-pass bandwidth to 171.3 MHz with 1pF capacitors and a power dissipation of only 0.67 mW per pole. With /spl plusmn/2.5 V supply, the -3 dB frequency and the center frequency can be extended to 286 MHz and 398 MHz respectively with power dissipations of 12.25 mW/pole and 8.17 mW/pole respectively. Both voltage- and current-mode structures are studied.