Abstract: This paper presents the circuit design and measured performance of a multi-band tuner for mobile TV applications. The tuner RFIC is composed of a wideband front-end, an analog baseband, a full integrated fractional-N synthesizer and an I²C digital interface. To meet the stringent adjacent channel rejection (ACR) requirements of mobile TV standards while keeping low power consumption and low cost, direct conversion architecture with a local AGC scheme is adopted in this design. Eighth-order elliptic active-RC filters with large stop band attenuation and a sharp transition band are chosen as the channel select filter to further improve the ACR preference. The chip is fabricated in a 0.35-μm SiGe BiCMOS technology and occupies a silicon area of 5.5 mm². It draws 50 mA current from a 3.0 V power supply. In CMMB application, it achieves a sensitivity of-97 dBm with 1/2 coding QPSK signal input and over 40 dB ACR.

Key words: tuner