A Micro Power High Precision SigmaDelta ADC with Adjustable Decimation Ratio In this paper a micro power high precision SigmaDelta ADC is presented. This ADC system is intended to digitize lowfrequency signals and so could be used as a voltage monitor or a temperature monitor in the power manager MCU. A secondorder onebit quantization modulator with Cascaded Integrator FeedBack (CIFB) structure is used. The decimation filter uses a threestage cascaded integrator comb (CIC) structure. The CIC filter decimation ratio is adjustable from 32 to 4096. This SigmaDelta ADC is implemented in 0.35xc2xb5m CMOS technology, simulation results show that the SigmaDelta modulator realizes the signal to noise ratio (SNR) of 88.4 dB with the sampling clock of 20.48kHz. When the decimation ratio of the CIC filter is set by 1024, the SNR of the SigmaDelta ADC is 86.0 dB, and the effective number of bits (ENOB) is 14.0 bits. Total power current of the modulator is less than 24xc2xb5A. The power current of the CIC filter is less than 3.12xc2xb5A.

A 0.8 V LowPower 3rd order SigmaDelta Modulator in 22 nm FDSOI CMOS Process for Sensor Interfaces We present the design of a lowpower 3rd order sigmadelta (xcexa3xcex94) modulator targeted for sensor applications. The circuit is implemented in the 22 nm Fully Depleted Silicon on Insulator (FDSOI) CMOS process technology from GlobalFoundries. The modulator features a singleloop feedforward architecture. Lowvoltage operation of the fullydifferential switchedcapacitor based modulator is achieved with enhanced bootstrapped switches for highly linear sampling., and operational transconductance amplifiers (OTAs) operating in weak inversion. The onchip area of the modulator is 0.193 mm2. The measurement results show that operating over a signal bandwidth of 500 Hz at a nominal supply voltage of 0.8 V and a sampling rate of 512 kHz., the modulator achieves a peak signaltonoiseanddistortion ratio (SNDR) of 89 dB and a dynamic range of 94 dB. The total average power consumption of the designed modulator, including that of the auxiliary circuits, is 170 xc2xb5W.