CMOS RF NMR Biosensor & Dual-Mode Pipelined ADC

Wednesday, March 24, 2010
7:00 PM
Free and open to the public

I will present two of my recent works. First, I will present the work that showcases how silicon radio-frequency (RF) chips can be used not only for wireless RF applications, but also for biomolecular sensing aimed at low-cost disease screening. The main function of the RF chip is to manipulate and monitor the dynamics of protons in water via nuclear magnetic resonance (NMR). Target biological objects such as cancer marker proteins alter the proton dynamics, which is the basis for the biosensing. The high sensitivity of the RF chip made possible the construction of an entire NMR system around the RF chip in a 100-g platform, which is 1200 times lighter, yet 150 times more spin-mass sensitive than a state-of-the-art commercial benchtop NMR system. The system can become a useful addition in pursuing disease detection in a low-cost, hand-held platform.

Second, I will present the design of a high figure-of-merit (FOM) pipelined ADC, made possible by a new, dual-mode-based digital background calibration technique that altogether corrects errors caused by amplifier gain insufficiency and nonlinearity, and capacitor mismatches. The calibration enables the intentional use of low-gain single-stage op-amps to save power. It improves the measured SNDR and SFDR by 16 dB and 28 dB respectively, leading to the FOM of 155 fJ/conv-step.

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Nan Sun

Harvard University