Sige Bicmos Op Amp Technology Research

With the development of wireless communication, the semiconductor devices and integrated circuit which based on Si technology can't meet the requirement of technique. SiGe BiCMOS could satisfy the demand of application well due to high performance and low cost, so, it's necessary to study the SiGe BiCMOS technique. In this dissertation, SiGe HBT device and SiGe BiCMOS high speed operational amplifier (op) are designed successfully by studying SiGe HBT theory and SiGe BiCMOS circuit characteristics.Based on the analysis of frequency characteristic and direct current characteristic, optimized design principles and the relationship between electrical parameter and structure parameter are given. After that, the device structure is designed and the Medici software is employed to do simulation. The result shows that the current gain achieved 300 and the fT is more than 30GHz.Based on the study of circuit cells which are applied in SiGe BiCMOS operational amplifier, the telescope cascode configuration is selected to realize high speed and high gain. In the process of the circuit design, SiGe HBT and MOS devices must be arranged properly in order to realize advantage complementarity. Using SiGe BiCMOS darlington configuration as the input stage, the input resistance is increased by the MOS devices while the transconductance of SiGe HBTs is maintained. In the same time, the equivalent input noise is controlled well because of the SiGe HBTs'good noise performance in the input stage. For the demand of output swing, the bias is provided by high-swing cascode current mirrors. The common-mode feed back (CMFB) circuit is realized by MOS differential pairs which operated in saturation region so as to improve the loop gain of the CMFB.According to the TSMC 0.35μm SiGe BiCMOS model, the circuit simulation is finished by the spectre in cadence. The simulated DC gain of the op is 87dB and its unity gain frequency is 2.0GHz at a phase margin of 59.3 degrees. The op dissipates 23mW power, has a differential output swing of 2.4V and the equivalent input noise is 4.0nV/ Hz1/2. This op settles to 0.01% accuracy within 2nS.