In this paper we report a 3rd-order Gm-C filter based on pseudo-differential continuous-time transconductors for applications in low-voltage systems over VHF range. By using a 0.18 µm pure digital CMOS process, a prototype low pass filter with -3 dB frequency programmable from 38 MHz to 213 MHz confirms the feasibility of the proposed filter in applications such as data storage systems.

This work describes a novel structural design for nth-order (n2) transconductance and grounded capacitor (Gm-C) filters with multiple loop feedback technology. The proposed design largely focuses on elucidating the relationship between the Gm-C filter structure and the feedback matrix, allowing us to systematically generate and formulate general design equations. The proposed design allows many new interesting filter configurations to be produced alongside some known structures. Furthermore, numerical design examples and simulation results verify the feasibility of the Gm-C filter approach.