DESIGN AND ANALYSIS OF INTEGRATED OPERATIONAL AMPLIFIER WITH LOW NOISE AT LOW FREQUENCY

The design principle is described for low frequency integrated operational amplifier XD1531 with low noise. The design procedures of both circuit and mask pattern are considered. The circuit structure of the first stage is designed with the methods for obtaining low noise at low frequency. The measures for decreasing the low frequency noise, especially the surface 1/f noise, are used for mask pattern design. By comparing its characteristics with those of other products at home and abroad, it is shown that XD1531 has lower noise in low frequency region than others and the design method is effective for bringing low noise.