Fully‐differential flipped‐source‐follower low‐pass analogue filter in CMOS 28 nm bulk.

This study presents a novel low‐pass continuous‐time filter based on the voltage flipped‐source‐follower (SF). The filter efficiently operates in CMOS 28 nm and improves the SF filters state‐of‐the‐art thanks to a dedicated circuit that operates in fully‐differential fashion (instead of the pseudo‐differential typically used in state‐of‐the‐art SF filters) with a dedicated Common‐Mode‐Feedback circuit. Thus this work extends the application of the SF filtering stages to the nm‐range technologies where threshold voltage (VTH) is only two times lower than the supply voltage (VDD) for what regards standard‐process MOS transistors. In order to validate the design concept, the proposed filter has been designed in CMOS 28 nm technology. Extensive simulation results of a 131 MHz −3 dB frequency proof‐of‐concept second‐order filter are proposed. The device consumes 510 µW power from a single 1 V supply‐voltage. In‐band integrated noise is 160 µVRMS and IIP3 is 19 dBm for 20 and 21 MHz input tones frequencies. Simulation results lead to 166 J−1 figure‐of‐merit, outperforming the analogue filter state‐of‐the‐art. [ABSTRACT FROM AUTHOR]