---

In this study, a dual-mode Delta Sigma modulator for both ‎WLAN and GSM standards has been designed. In order to reduce the power consumption and to ‎optimize the chip area, a reconfigurable structure, which can be separately tuned for these two different ‎applications, is used. The proposed modulator is based on a multi-bit VCO instead of a conventional flash ‎quantizer. Due to the possibility of lower voltage application and lower power consumption, the VCO-‎based Delta Sigma modulator can be a good choice especially for sub-100nm technology, where the ‎performance of the analog circuits becomes limited, and conversely superior switching rates can be ‎achieved. The idea of VCO-based Delta Sigma converter has been recently developed, however the multi-‎mode reconfigurable structure is proposed and analyzed for the first time in this research. The proposed ‎modulator is dedicated to operate with the two major WLAN and GSM standards. It is designed at ‎system level in general, but the VCO part is implemented at transistor level using 180nm CMOS ‎technology. The simulations’ results show a saving of at least 86% of power consumption in the ‎VCO part, in the GSM standard compared to WLAN.‎