Programmable SiGe BiCMOS Low-Pass Filter for a Multicarrier WCDMA Base-Station Receiver

摘要

SiGe BiCMOS low-pass filter for a multicarrier WCDMA base-station receiver is described in this paper. The 4th-order Chebyshev filter with a 0.1-dB passband ripple is designed to drive a high-resolution A/D converter. The -3-dB frequency of the implemented filter can be programmed to four different bandwidths: 2.5 MHz, 5 MHz, 7.5 MHz, and 10 MHz depending on the number of received WCDMA channels. The filter achieves +9.7-dBV in-band IIP3, +20dBV out-of-band IIP3, and 8.5-nV/radicHz input-referred noise density with 10-MHz bandwidth. The circuit uses a 2.5-V supply and has been fabricated in a 0.25mum SiGe BiCMOS process