Performance Evaluation of a Low Pass Filter Based on Super-Source Follower Using 18nm Technology

This paper presents the performance analysis of a power-efficient and optimized 2nd-order analog low-pass filter designed using an enhanced class AB super source follower (SSF) in $18-\text{nm}$ technology. The proposed filter significantly improves power efficiency, bandwidth, noise performance, and linearity compared to traditional Class A SSF-based filters. The measurement result presents a DC gain of $\mathbf{- 1 . 9 9 ~ d B}$ and a bandwidth of 293 kHz, respectively, and an integrated in-band noise of $65.24 \mu \text{Vrms}$. The power consumption is notably reduced to $8.691 \mu \text{W}$, representing a $44.4 \%$ decrease compared to the class A counterpart, which consumes $15.64 \mu \text{W}$. For a $50 \text{kHz}, 0.4 \text{Vpp}$ input signal, the total harmonic distortion (THD) is measured at −70.44 dB, which is 7.67 dB better than the class A version. The third-order intermodulation distortion (IM3) is measured at −31.34 dB for a $350 \text{kHz}, 0.4 \text{Vpp}$ input signal, with an IIP3 of −30.42 dBm. Recommended topology outperforms typically Class A filter and Class AB implementations in terms of linearity, noise reduction, and power efficiency.