A Novel High-Pass Filters Implementation by Fully Differential Op Amp Integrators


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The design of low-pass and bandpass filters is often based on the leapfrog method which, in these cases, yields integrator-based structures. Using the leapfrog signal flow graph (SFG) for the simulation of high-pass filters leads to a differentiator-based structure which could be implemented by Gm-C or CCII conveniently. However, when we use Op amp RC integrators for good linearity, we have to use integrators, and not differentiators, for reasons related to the excessive noise behavior of the latter. This paper presents a new leapfrog SFG implementation by fully differential Op amp integrators, which combines good high-frequency properties with good noise properties. The direct SFG simulation method and single-ended output Op amp can also based on integrators, but all of them will lead to a relatively high circuit complexity and a high noise level. A design example is included, with comparisons of gain responses and noise densities.



Edited by:

Mohamed Othman




H. D. Zhang et al., "A Novel High-Pass Filters Implementation by Fully Differential Op Amp Integrators", Applied Mechanics and Materials, Vols. 229-231, pp. 1531-1534, 2012

Online since:

November 2012




[1] Su K. Analog Filters[M]. Kluwer, Norwell, MA, (2002).

[2] Sun Yichuang. Synthesis of leap-frog multiple-loop feedback OTA-C filters[J]. IEEE Transaction on Circuits and Systems, 2006, 53(9): 961-965.

DOI: https://doi.org/10.1109/tcsii.2006.879095

[3] Song Shu-xiang, Yan Guoping. Nth order current mode leapfrog-type filter design based on CCCII[J]. Journal of Yunnan University, 2009, 31(2): 129-134(in Chinese).

[4] Maciej Guzinski, Signal flow graph structure of high-pass filter useful for OTA-C, 0-7803-3636-4197 $10. 00 © 1997 IEEE.

[5] F. E. I. Girling and E. F. Good. 1970. Active filters 12. The leap-frog or active ladder synthesis, Wireless World 76, p.341–345.

[6] Y. Tsividis, M. Banu, and J. Khoury, Continuous-Time MOSFET-C Filters in VLSI, IEEE Journal of Solid State Circuits Vol. SC-21, No. 1 Feb. 1986, pp.15-30.

DOI: https://doi.org/10.1109/jssc.1986.1052478