A dual-band, dual-conversion receiver integrated from LNA to analog baseband circuitry is presented. The lowpass filters integrate a cutoff frequency auto calibration scheme and can be automatically tuned from 6-MHz to 17-MHz with ±3% accuracy. This design is suitable for multistandard, multi-bandwidth applications, such as 802.11a/b/g and the incoming 802.11n, while the RF front-end is shared. The chip was fabricated in TSMC 0.25um CMOS process with 2.5V power supply. The noise figure is 2.8dB/3.9-dB for 2.4/5-GHz bands at the maximum gain setting, and the iIP3 of 10/-3-dBm is achieved for 2.4/5-GHz bands at the minimum gain. The receiver provides a programmable gain of 88/78-dB in 2dB steps and consumes 51/54-mA current for 2.4/5-GHz bands, respectively.

A direct conversion transmitter for WCDMA application is presented in this paper. The baseband DC offset voltage of this transmitter is adjustable, such that carrier leakage power at the quadrature modulator output can bc minimized. With this adjustable DC offset voltage, gain control with large dynamic range can be distributed in baseband to implement accurate gain control. An autocalibration algorithm is also implemented in the baseband filter to adjust its cutoff frequency lo 3.2MHz. Tho current consumption of the transmitter is only 46.4mA under 2.7V power supply and can be further reduced at smaller output power. The measured E V M

Absfract -A WCDMAiDCS dual-band RF front-end receiver IC fabricated in a 0.35-pm SiGe BiCMOS technology is presented. This RF receiver uses P novel fullydifferential LNA with dual input-stages to replace the requirement of paralleling two similar LNAs in previous dual-band designs. This chip dissipates 24mA from a 2.7-V supply and can be used in direct-conversion or low-IF receiver. The measured voltage gain, PldB and iIP3 are 32dB, -25dBm and -1SdBm, respectively.

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