A 1.2-V, 1.6-mW, 107-dB Dynamic Range, and 99.5-dB SNDR Sigma-Delta Modulator for Digital Audio in 0.25-μm CMOS

This paper presents a 1.2-V, 1.6-mW, and high-resolution sigma-delta modulator for digital audio. It uses a modified low-swing integrator outputs 4th order single-loop topology. Modulator coefficients are optimized for higher overload level factor and low power. A low-power two-stage class A/AB OTA with modified common mode feedback (CMFB) circuit in the first stage is used in the first integrator. To reduce the power consumption, a simple folded-cascode OTA is used in the last three integrators. Simulation results with OSR of 100 give SNDR and dynamic range (DR) of 99.5 dB and 107 dB including the circuit noise in the 25 kHz signal bandwidth, respectively. The circuit is implemented in a 0.25-μm standard CMOS technology.

کلیدواژه ها:

Sigma-Delta Modulation ، Operational Amplifiers ، Switched-Capacitor Circuits