论文信息 - Improvement of stop-band attenuation for the Sallen-Key low-pass filter

Improvement of stop-band attenuation for the Sallen-Key low-pass filter

A Sallen-Key low-pass filter configuration with improved stop-band attenuation is presented. The proposed configuration simply connects an additional capacitor which is in parallel to the filter's output to effectively reduce the high-frequency impedance and consequently the undesired high-frequency feedthrough. The relationship between the additional capacitor and high-frequency feedthrough is also investigated to verify its feasibility. The proposed Sallen-Key low-pass filter configuration combines the advantages of simplicity and improved stop-band attenuation which make it attractive for practical application. The simulation and measurement results also confirm the theoretical prediction.

Hsin-Wen Ting | Hung-Yu Wang

[1] Lawrence P. Huelsman. Active and Passive Analog Filter Design : An Introduction , 1993 .

[2] S. Ramet. A low-distortion anti-aliasing/smoothing filter for sampled data integrated circuits , 1988 .

[3] John G. Webster,et al. Medical Instrumentation: Application and Design , 1997 .

[4] Phillip E Allen,et al. CMOS Analog Circuit Design , 1987 .

[5] Behzad Razavi,et al. Fundamentals Of Microelectronics , 2006 .

[6] P. Geffe. Exact synthesis with real amplifiers , 1974 .

[7] M. E. Valkenburg,et al. Design of Analog Filters , 2001 .

[8] Jiří Sedláček,et al. Low-pass biquadratic filters with high suppression rate , 2009 .

[9] Chao-Shiun Wang,et al. A CMOS low-IF programmable gain amplifier with speed-enhanced DC offset cancellation , 2002, Proceedings. IEEE Asia-Pacific Conference on ASIC,.

[10] R. Sallen,et al. A practical method of designing RC active filters , 1955, IRE Transactions on Circuit Theory.

[11] George S. Moschytz,et al. Fundamental frequency limitations in current-mode Sallen-Key filters , 1998, ISCAS '98. Proceedings of the 1998 IEEE International Symposium on Circuits and Systems (Cat. No.98CH36187).