Design of ultra-low spurs multi-stage feedback bandpass filter
Yu Jigang，F(xiàn)u Chao
No.58 Research Institute,， China Electronics Technology Group Corporation
Abstract： In the testing and measurement of high-precision data acquisition systems, high-quality bandpass filters are crucial. However, using passive components to achieve low-frequency and high-quality filters requires large inductors, and the size and cost are daunting. This design uses the high-performance fully differential audio amplifier OPA1632D to design a sixth order active 1kHz bandpass filter. The bandpass filter adopts a multi-level feedback design, with a simple principle structure and low design cost. The simulation test results using TINA-TI are good, and it is actually used for front-end filtering testing of high-performance analog-to-digital converter AD7961. The SNR and SFDR dynamic indicators are close to the theoretical values in the manual. Simulation and practice have shown that the design of this filter meets the needs of high-precision data acquisition front-end filtering.
Key words : bandpass filter,；audio amplifier,；OPA1632,；multi-level feedback；AD7961,；SNR
