Q-enhanced LC bandpass filters for integrated wireless applications

Abstract

Q-enhanced LC filter technology offers an alternative to the use of direct conversion techniques for implementing fully integrated receivers. Design and performance issues for QE LC filters are discussed and a fully integrated 850-MHz, two-pole, bandpass filter with an 18-MHz 3-dB bandwidth is reported. The prototype design is implemented in a standard 0.8-m CMOS process and achieves a rejection of over 50 dB at 100 MHz offset, an in-band dynamic range of 75 (90) dB when used in a system with a 1-MHz (30-kHz) final IF bandwidth, and a third-order intercept point that exceeds +25 dBm at an 80-MHz offset from the passband center. Index Terms-Integrated receiver, Q-enhanced LC filter, RFIC, spiral inductor. . He is now with the Wireless RF Department, Semiconductor Group, Texas Instruments Incorporated, Dallas, TX 75243 USA.A. S. Wyszynski was with Microtune, Inc., Plano TX 75074 USA. He is now at 1512 Highland Circle, Little Elm, TX 75068 USA.Publisher Item Identifier S 0018-9480(98)09227-8.

Managing linearity in radio front-ends

“…By placing a negative resistance of value −|R P | in shunt with this network, the effective Q can be shown to be Q e f f = {|R P |/ (|R P | − R P )} Q [31]. The selectivity of the design is thus enhanced through the use of a negative resistance.…”

Reduced External Hardware and Reconfigurable RF Receiver Front Ends for Wireless Mobile Terminals

“…10.4) with frequency tuning has been shown in CMOS [20]. Theoretically, these integrated filters can replace the external preselect filters.…”

A Sallen and Key Active Filter Using SiGe BiCMOS Technology

“…Many solutions were proposed in the literature. Some of them are based on the loss compensation by using a negative resistance [1][2][3]. Others are based on replacing the passive inductance by an active one [4,5].…”