Ultra-low power multi-channel data conversion with a single SAR ADC for mobile sensing applications
Based on the recently emerging compressive sensing theory, the paper proposes an ultra-low power multichannel data conversion system whose architecture is almost as simple as a single SAR ADC. The proposed architecture is capable of simultaneously converting multi-channel sparse signals while running at the Nyquist rate of only one channel. A chip is fabricated in a 0.13μm CMOS process. Operating at 1MS/s, the SAR ADC itself achieves a 66dB SNDR and a 25fJ/step FoM at 0.8V. Using convex optimization methods, 4-channel 500kHz-bandwidth signals can be reconstructed with a 66dB peak SNDR and a 41% max occupancy, leading to an effective FoM per channel of 6.25 fJ/step.