小型地磁传感器的低噪声前置放大电路设计.PDF

2012 26 6 Vol. 26 No. 6 2012 ( 96 ) JOURNAL OF TEST AND MEASUREMENT TECHN OLOGY ( Sum No. 96) :2012) 1 1 1 1 胡靖华 , 潘孟春, 田武刚 , 胡佳飞 ( , 4 10073) : 10 nV/ Hz , nV . , , Multisim , . , , 3.7 nV/ Hz@ 3. 5 Hz, 110 dB, 100~ 1 000 . : ; ; ; : T N722 : A doi: 10. 3969/ j. issn. 2012.06. 010 Design of Low Noise Preamp ifier Circuit of Sma size Geomagnetic Sensor 1 1 1 1 HU Jinghua , PAN Mengchun , T IAN Wugang , HU Jiafei ( Dept. of Instrument Science and Technology, College of Mechatronics and Automation, National University of Defense T echnology, Changsha 410073, China) Abstract: The output noise voltage level of some smallsize geomagnetic sensors is about 10 nV/ Hz. How ever, existing comparative level preamplifier products are so large that could not satisfy conditioning require ment. To solve the problem, a smallsize low noise amplifier circuit based on differential input is designed. T he design principles of inputstage are expounded in this paper. Key indicators of equivalent input noise volt age and gain are simulated by Multisim. Finally, simulation and testing results are given, and testing results show that the circuit has achieved low noise voltage of 3. 7 nV/ Hz@ 3. 5 Hz, high CM RR of 110 dB and variable gain from 100 to 1 000. Key words: low noise; preamplifier; noise simulation; noise voltage measurement [ 1,2] ( MEMS ) , , , . . , , 3. 5 K. 12 nV/ Hz@ 3. 5 Hz, : : GMR ( :( 198