This work presents two novel topologies of cascade ΣΔ modulators with unity signal transfer function that avoid the need of digital filtering in the error cancellation logic. The combination of these two aspects make them highly tolerant to noise leakages, very robust to non-linearities of the circuitry and especially suited for low-voltage implementations at low oversampling. Behavioral simulations are presented that demonstrate the higher efficiency of the proposed topologies compared to existing cascades intended for wideband applications.This work has been supported by the Spanish Ministry of Science and Education (contract TEC2004-01752/MIC) and the Spanish Ministry of Industry, Tourism and Commerce (FIT-330100-2006-134 SPIRIT).Peer reviewed