The Research Of Switched Current (Si)∑-Δ Modulators For Multi-standard RF Receivers

The application of wireless communication, sensor and precise technology of measurement has become increasingly significant as the electronics information technology and communication technology has amazingly developed, especially the application of communication, which give rise to hugely economic performance and nation strategy. Thus, it is got the people of different nation’s high opinion and extensively and thoroughly research. Moreover, under the circumstance of communication market, users will specify their various request of communication quality and communication standard according to their different situation. Therefore, the design of modulator should thoroughly consider the factor of communication qualities and former compatibility problem of communication standard in different stage and different type communication, so as to urge the people of science and techology to research and design electroic IC with highly performance and better compatibility, in order to satisfy the communication requirement of communication users.Firstly, the device physics is simplely introduced in this paper, and then the definition and characteristic of switched current and∑-△modulator design is detailedly described (the noise is thoroughly analysed), in addition the design parameter index of∑-△modulator is extensively introduced and calculated also in this paper. Under the basic design circumstance, several important design parameter index of∑-△modulator is extensively introduced and analysed (the power estimation process of∑-△modulator is detailedly introduced). Based on that, using an SI2-1cascoded∑-△modulator module as a design living example, the design distance travelled by a stream of water of switched current modulator is introduced. Based on that, a dynamic element matching (DEM) circuit design technology of improving the∑-△modulator capability is introduced. Moreover, the RF receiver structure, the basic communication standard. the ADC test method and single frequency and duplexing frequency test constructions are simplely described.At the end of this paper, combining the knowledge of switched current,∑-△modulator and RF receivers, design an SI2-1cascoded∑-△modulator module, which satisfy the noise shape module of the RF receiver, test and verfication the∑-△modulator with circuit simulation soft Spice and mathematics simulation soft MATLAB; thus, it is proof that the switched current techology to design the∑-△modulator with better performance superiority, replacing the SC technology, satisfying the low power low voltage high frequency application with technology of deep micron and nano meter and possessing extensively application future. Finally, some circuit design technology with capability improvement are introduced, such as, avoiding the circuit with latch-up effect to add the construction of guard rings or to use the SOI techology; eliminating the gradient effect of technology mismatches and improving the system match capability, a commom-centroid configuration and addition of dummy devices may be used in the circuit layout design.