Wide Tunable Highly Linear Triode-based CMOS OTA Using a New gm3 Cancellation Technique

In this paper, a new method is proposed which improves linearity of an 0.18μm CMOS OTA in the whole transconductance tuning range. The proposed method is based on gm3 cancellation in which high linearity of output current of OTA in the whole tuning range is preserved through matching positive and negative values of gm3 of triode and sub-threshold transistors. Using this method, the total harmonic distortion (THD) of OTA remains less than -55.5 dB throughout its transconductance tuning range from 4.3 A/V to 51.8 A/V. Using the proposed OTA, a 1.8V low-pass Gm-C filter is implemented. The power consumption of filter changes between 0.7mW and 1.3mW and its cut-off frequency can be tuned from 756kHz to 9.7MHz.

کلیدواژه ها:

OTA ، Gm-C filter ، tunability ، gm3 cancellation