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A 250 MHz analog baseband chain for ultra-wideband was implemented in a 1.2 V 0.13 Â¿ m CMOS process. The chip has an active area of 0.8 mm2. In the analog baseband, PGAs and filters are carried out by current-mode amplifiers to achieve wide bandwidth and wide dynamic range of gain, as well as low noise and high linearity. Besides, a current-mode Sallen-Key low-pass filter is adopted for effective rejection of out-of-band interferers. A 6 th-order Chebyshev low-pass filter realized in Gm-C topology is designed in the baseband chain for channel selection. Digitally-assisted DC-offset calibration improves second-order distortion of the entire chain. The design achieves a maximum gain of 73 dB and a dynamic range of 82 dB. Measured noise figure is 14 dB, an IIP3 of -6 dBV, and IIP2 of -5 dBV at the maximum gain mode. The analog baseband chain consumes 56.4 mA under supply of 1.2 V.
Date of Publication: Feb. 2010