A 95 dB dynamic range automatic gain control circuits and systems for Multi-standard Digital TV tuner

摘要

A 95 dB dynamic range automatic gain control (AGC) circuits and systems for Multi-standard Digital TV (DTV) tuner has been presented. A novel automatic gain control method composed of RFAGC and IFAGC is proposed with improved SNR. A wideband single-ended LNA based on current-reuse technique with low temperature variation is proposed. The complete AGC circuits are fabricated in six-metal 0.18-µm CMOS technology and consume DC current of 32.5 mA from a 1.8 V supply. The RF front-end circuit achieves 90 dB maximum gain, 95 dB gain control range, a 4 dB noise figure and an IIP3 higher than −28 dBm at the maximum gain.