Low Power, Third Order Σ Δ Modulator with Cross-Coupled Paths for WCDMA Applications

This architecture realizes a third order shaping of the quantization error starting from a 3-Path Sigma-Delta architecture. Each path is made by a first order modulator and the Noise Transfer Function (NTF) is obtained by crosscoupling the quantization errors of the three paths to obtain the missing terms in the NTF. Simulation results meeting the WCDMA requirements obtain signal bandwidth of 1.92 MHz with an over-sampling-ratio (OSR) of 10 and an effective number of bits (ENOB) equal to 10. The resulting power consumption is lower than 2.8 mW.