A Low-Voltage and Area-Efficient Adaptive SI SDADC for Bio-Acquisition Microsystems

An ultra-low voltage adaptive Sigma-Delta Analog-to-Digital Converter (SDADC) with a 10-bit dynamic range for bio-microsystem applications is presented. The proposed SDADC includes a Switched-current Sigma-Delta Modulator (SISDM) and a digital decimator. Moreover, a new single-multiplier structure is presented to implement the Finite Impulse Response (FIR) digital filters which are the major hardware elements in the decimator. Measurement results show that the SISDM has a dynamic range over 6 dB and a power consumption of 180 muW with an input signal of 1.25 kHz sinusoid wave and 5 kHz bandwidth under a single 0.8 V power supply for ENG signals. Besides, the post layout simulations of SDADC including SISDM and decimator reveal that the dynamic range is still over 60 dB without harming by digital circuits.