A 100KS/s 65dB DR Σ — Δ ADC with 0.65V supply voltage

We present a low-power Sigma - Delta modulator to be used in the baseband sections of wireless sensor network receivers with 0.65 V V_dd operation. The design is optimized for low-power consumption and low operating supply by minimizing operational amplifier open-loop gain. Simple differential pair amplifiers with ap 40 dB of open loop gain and low noise factor are employed as the integrator cores and guarantee a spurious-free dynamic range(SFDR) of 63 dB. The prototype employs only standard V_th devices and dissipates 27 muW to achieve 65 dB dynamic range in a 50 KHz bandwidth, including regulated bias. The peak SNDR of 59.5 dB corresponds to a figure of merit (FOM) of 0.36 pJ/Conv.Step.