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A variable-gain low-noise amplifier with capacitive step attenuators is presented. In order to improve linearity at medium gains settings, digital gain control is performed using a current-splitting technique at the cascode transistors. The fabricated LNA shows an IIP3 increase with constant OIP3, from -1.1 dBm at 25.8 dB gain to 3.5 dBm at 21.2 dB gain. Using capacitive attenuator control, a wide gain range of over 42.7 dB is achieved. Using a 0.5-mum BiCMOS process, the proposed LNA shows an NF of 1.5 dB at 650 MHz and a power consumption of 15.4 mW under 2.9 V supply voltage. The fabricated tuner-IC, including the proposed LNA, satisfies all requirements pertinent to DVB-H reception, with sufficient margins for practical integration. Under typical DVB-H reception scenarios involving strong interferers, measurement results and analytical calculations showed good consistency at various gain settings.

A fully integrated direct conversion DVB-H tuner is realized in a 0.5-mum SiGe BiCMOS technology. To meet the stringent linearity requirement while keeping low power consumption, novel linearization techniques for a variable-gain low-noise amplifier (VG-LNA) and a mixer are proposed. The proposed linearized VG-LNA has a variable gain range of over 50 dB, noise figure of less than 2.6 dB over the frequency range from 200 to 1000 MHz, and IIP3 of more than -10 dBm at a current consumption of 2.1 mA. The quadrature mixer with the proposed linearization technique achieves OIP3 of more than 25 dBm at a current consumption of 5 mA. In addition, a new offset-cancel feedback is introduced for the baseband block of a direct conversion receiver, which keeps the high-pass cutoff frequency independent of the baseband VGA gain. The fabricated tuner IC satisfies all the DVB-H requirements at a power consumption of 184 mW

A single chip direct conversion DVB-H tuner with a distortion compensated variable gain LNA is implemented in 0.5mum SiGe BiCMOS. The LNA exhibits 0dBm IIP3 and 2.8dB NF at 860MHz. A new offset cancel feedback is introduced that keeps the cutoff frequency independent of the baseband gain. The IC consumes 184mW at 2.8V while achieving a sensitivity of -96dBm for QPSK, CR=1/2 signal

A 160mW low-IF single-chip tuner for a mobile ISDB-T receiver is realized in SiGe BiCMOS. Its 25mW variable gain LNA shows 2.7dB NF and 62dB variable gain range. The 20mW switched-capacitor channel selection filter exhibits 80dB out-of-band rejection and 11nV//spl radic/Hz input referred noise.