An Energy-Efficient 20 GS/s-Equivalent Time-Interleaved Switched-Sampling Front End for Direct IR-UWB Acquisition

Waveform-based impulse-radio ultra-wideband (IR-UWB) recognition requires retaining pulse features that scalar energy or peak detectors do not resolve. This paper presents an eight-channel time-interleaved switched-sampling array (TI-SSA) that captures a finite pulse window and holds an analog voltage vector for external quantization. Complementary switches, dummy compensation, programmable timing, symmetric routing, and parallel bonding address sampling and input-transfer errors. Fabricated in 180 nm CMOS, the macro occupies 0.06 mm2 and supports nominal 50 ps sample spacing, equivalent to 20 GS/s within the capture window. Measurements with a shared timing reference characterize phase-coded pulses at two nonzero amplitude levels through waveform similarity, amplitude error, and constellation projections. The four-state and 16-state modes consume 2.59 and 4.52 mW, respectively, excluding the LNA, external ADC, and FPGA. These modes support nominal data rates of 300 and 400 Mb/s. The measured waveform and constellation results demonstrate discrimination of the predefined phase and amplitude states. The corresponding macro energies per acquired sampling bin are 4.32 and 5.65 pJ/bin, respectively, providing an energy-efficient hardware interface for future learning-assisted pulse recognition.