A CMOS 140-mW Fourth-Order Continuous-Time Low-Pass Filter Stabilized With a Class AB Common-Mode Feedback Operating at 550 MHz

A 550-MHz linear-phase low-pass continuous-time filter is described. The operational transconductance amplifier (OTA) is based on complementary differential pairs in order to achieve high-frequency operation. A common-mode feedback (CMFB) based on a Class AB amplifier with improved stability at high frequencies is introduced. Results for the stand alone OTA show a unity gain frequency of 1 GHz while the excess phase is less than 5. The filter is based on Gm-C biquads and achieves IM3 < -40 dB for a two-tone input signal of -10 dBm each. The power consumption of the fourth-order filter is 140 mW from supply voltages of 1.65 V. The chip was fabricated in a standard 0.35-m CMOS technology. 2006 IEEE.

A CMOS 140-mW Fourth-Order Continuous-Time Low-Pass Filter Stabilized With a Class AB Common-Mode Feedback Operating at 550 MHz Academic Article