Ultra-low power MOSFET-only micromation multi-bit quantizer for implantable neural applications

Several power and area efficient multi-bit quantizers are discussed in this paper. Through the comparison and analysis of the reported quantizers, a novel ultra-low power MOSFET-only micromation one for implantable neural applications is proposed to optimize the area and power consumption with the use of high density MOSCAP and dynamic comparators. Simulated in a 0.18 μm 1P6M CMOS process, the density of the proposed series-PMOS capacitor reaches 2.1fF/μm² at a 1.2 V supply voltage, which is almost 1.5 times higher than that of the traditional Metal-Insulator-Metal (MIM) capacitor. The current power consumption of the proposed 9-level quantizer is only 0.14 μA clocked at 512 kHz, and its area cost is 11200 μm². Compared with the conventional architecture, over 95% power and 80% area are saved. The simulation results show that the proposed quantizer is suitable for Delta-Sigma modulator designs.