Research On Wideband And Low Power Consumption △ -ΣADCs

With the rapid advance of CMOS technology, digital signal processing techniques can be used at clock frequencies reaching into the microwave region. This permits the digital transmitters that can deal with the radio-frequency signal. In the digital transmitter, the △-Σ ADCs is a key block. Because of their inherent oversampling and noise shaping, the matching requirements on analog components are significantly relaxed, which makes the △-Σ ADCs became the mainstream technology on high precision analog-to-digital converter.The origin of △-ΣM and the basic principle of △-ΣM are introduced. According to the design parameters, the classification of △-ΣM is analyzed. Meanwhile, the modulator technologies are expounded. There are several technologies:low distortion, noise coupling technology, zero optimization technique and double sampling technique. But these techniques do not solve the feedback path timing issue, so the extra loop delay and the shifted loop delay are mentioned. The realization of the integrator and the adder are discussed.The article utilizes the shifted loop delay technology, and the loop delay is shifted at the feedback path and the loop filter output from different integrator. The coefficients of modulator are analyzed. Combine with the noise coupling and zero optimization technology, the paper puts forward some improvement structure, and the eliminating active adder structure is also analyzed. To verify the effect of the proposed topology, a few designed examples were analyzed and simulated with Simulink.