A Multi-Channel Direct-Digital-Conversion Front-End Based on Current-Domain Frequency Division Multiplexing

Multi-channel multiplexing front-ends based on current domain-frequency division multiplexing (CD-FDM) can alleviate the contradiction between higher single-channel power and the number of channels. Direct digital conversion (DDC) architecture eliminates the amplification stage, saving power consumption and area. However, research on multi-channel DDC is still lacking up to date. This brief demonstrates a four-channel CD-FDM DDC front-end for the first time. The prototype was fabricated in a 180 nm BCD process, occupying a core area of 1.602 mm2. The measurement shows a total harmonic distortion (THD) of 0.073% at a 260 mVpp input. The signal-to-noise-and-distortion ratio (SNDR) and dynamic range (DR) are 54.55 dB and 62.52 dB, respectively. The integrated noise from 0.5 Hz to 9.77 kHz is measured at $5.79~\mu $ Vrms, corresponding to a 9.34 noise efficiency factor (NEF). The experimental results demonstrate it to be a promising candidate for multi-channel artifacts-tolerant front-ends with high compactness as well as high energy efficiency.