Automatic tuning of RC filters and fast automatic gain control for CMOS low-IF transceiver

Automatic tuning of RC filters and fast automatic gain control (AGC) of cascaded programmable amplifiers were proposed and verified by a 0.18 /spl mu/m CMOS prototype IC. The tuning circuit includes a dummy 1st-order filter, a comparator and a simple digital circuit and tunes /spl plusmn/28 % time-constant variation of filters within /spl plusmn/4.4 % accuracy. The AGC circuit adopts a novel feedforward technique with a digital timing control, which enables one-shot gain control and thus a fast settling.

[1]  Francois Krummenacher,et al.  A 4-MHz CMOS Continuous-Time Filter with On-Chip Automatic Tuning , 1987, ESSCIRC '87: 13th European Solid-State Circuits Conference.

[2]  T. Ooshima,et al.  Gain calibration and feedforward automatic gain control for CMOS radio-frequency ICs , 2003, 2003 Symposium on VLSI Circuits. Digest of Technical Papers (IEEE Cat. No.03CH37408).

[3]  John B. Hughes,et al.  High-linearity continuous-time filter in 5-V VLSI CMOS , 1992 .

[4]  K. Yamamoto,et al.  A 2.4 GHz RF transceiver with digital channel-selection filter for Bluetooth , 2002, 2002 IEEE International Solid-State Circuits Conference. Digest of Technical Papers (Cat. No.02CH37315).