Muhammed Mansoor C, B.Rekha, S.2026-02-032025International Journal of Circuit Theory and Applications, 2025, , , pp. -989886https://doi.org/10.1002/cta.70248https://idr.nitk.ac.in/handle/123456789/20581This paper proposes a novel, compact, and energy-efficient biquad which is derived from a folded single-branch transistorized (Formula presented.) -C structure. The biquad has a small number of active devices stacked between (Formula presented.) and GND rails and hence can be used satisfactorily in a low-voltage environment. The filter also inherits the benefits of folding in the circuit which makes the tuning of the filter easier and power independent. A fourth-order low-pass filter is used as a vehicle to illustrate the performance of the proposed biquad. The fully differential version of the filter is designed in 65-nm CMOS technology, operates with a supply voltage of 0.6 V, is biased with a current of 100 nA, has a (Formula presented.) 3-dB bandwidth of 15 kHz, and shows a dynamic range as high as 61 dB. The postlayout simulations along with FOM numbers show the superior performance of the filter. © 2025 John Wiley & Sons Ltd.Bandpass filtersEnergy efficiencyLow power electronicsStructure (composition)Active devicesAnalogue filtersBranch circuitsEnergy efficientFourth-orderLow PowerLow voltagesLow-pass filtersPerformanceSingle-branch circuitLow pass filters