Tunable Low Frequency Gm-C Low-Pass Filter using an OTA with Bootstrapping

This paper introduces the design and characterization of a \(Gm-C\) $Gm-C$ low pass filter aimed for very low-frequency applications. The main transconductor is based on bootstrapping techniques to reduce the transconductance of the OTA, thus avoiding large values of capacitors and resistors. The filter operation is demonstrated via experimental results from a fabricated prototype in a standard 0.18 \(\mu \) $\mu$ m CMOS process with an area of 0.14 \(\hbox {mm}^2\) ${\text{mm}}^2$ . The filter has a cut-off frequency tuning range from 2 to 18 kHz, an input-referred noise power spectral density of 5.1 \(\mu \) $\mu$ V/ \(\surd \) $\surd$ Hz @ 100 Hz, a dynamic range of 68 dB with a power consumption of 5.3 \(\mu \) $\mu$ W, and 1.8 V power supply.