Abstract
In recent years, due to the rapid development of medical technology, human Life is extended . This makes the rapid growth of biomedical electronic market, and also let the needs of the physiological signals measurement systems promoted grad- ually .A high precision analog-to-digital (A/D) converter is an important block in the physiological signals measurement systems ; we generally choose the delta-sigma A/D converter as the main architecture for the data converter . To be matching requ irements for the plan, a delta-sigma modulator which is applied in the bio-sensing system that could handle the signal capturing by the devices is implemented in this thesis . This thesis presents a one-bit second-order discrete-time delta-sigma modulator (DT-ΔΣM), and to be implemented with TSMC 0.18-μm 1P6M process . By using CIFB architecture make the STF to have better filtering performance at high frequency, and make the modulator to have better stability ; the input stage of the operational amplifier use the rail to rail architecture to raise the reliability of the system and ma- ke the modulator still function work even though the outpu swing of the integrat- or is larger . Also using the CDS technique in the first intergrator stage help to reduce the offset of component mismatches and suppress the 1/f noise . The whole delta- sigma modulator operating at 1.8V supply voltage, with 20KHz signal bandwidth, and oversampling ratio of 256, the designed modulator achieved signal to noise and distortion ratio(SNDR) of 93.26 dB, equivalent to the effective number of bits (ENOB ) 15.26 bits .The power consumption is 2.732 mW, the figure of merit (FoM) is 1.782 pJ/conv., and the core chip area is 668 x 278μm2 .