A 1.2-V 450-μW - Bluetooth Channel Filter Using a Novel Gain-Boosted Tunable Transconductor

A third-order G_m-C Chebyshev low-pass filter based on a novel gain-boosted tunable transconductor is presented. The transconductor employs local negative feedback for linearization controlling the drain voltage of the input transistors biased in the triode region. The gain boosted feedback amplifier is based on quasi-floating gate MOS transistors and its adjustable biasing current allows tuning the cutoff frequency of the filter. The filter is intended to be used in the baseband section of a zero-IF bluetooth low energy receiver and it has been fabricated in a standard 0.13-μm CMOS technology with a nominal cutoff frequency of 500 kHz. The power consumption of the overall filter is 450 μW with a supply voltage of 1.2 V. The measurement results show a third-order intermodulation distortion of -46.4 dB for two input tones located at the passband of the filter. The filter occupies a silicon area of 0.08 mm².