Once the initial ideal values have been calculated, practical solutions are created using off-the-shelf components. Analysis programs simulate the results after the user enters the appropriate values. Filter synthesis programs generate the required inductance (L) and capacitance (C) values. Modern circuit synthesis and analysis programs can quickly perform the otherwise tedious and time-consuming calculations for designing LC filters. Appendix A: Passive LC Filter Design and Analysis Filter Alignments and Properties As a trade-off, there is more pass-band ripple and stop-band ripple in Elliptic LC filters.įor more details on the various filter alignments shown in Appendix A of this application note. For example, Elliptic (Cauer) filters give the sharpest roll-off and are the least sensitive to component variation. Higher-order filter alignments use more components to give a sharper, more defined roll-off in attenuation of unwanted noise. The simplest LC filter consists of one inductor and one capacitor. There are many types of alignments, including those with the most commonly desired characteristics such as Butterworth, Bessel, Chebyshev, and elliptic. The alignment (type) of the filter determines the flatness of frequency behavior and the sharpness of the cut-off. The simplest to design and implement are the low-pass and high-pass types.Ĭoilcraft high-Q, tight-tolerance, surface-mount RF chip inductors and air-core inductors help you achieve top performance in all of these LC filter categories. Selecting the exact values of the parts for a particular application requires high quality components as well as complete specifications and performance models. While ideal filters would pass desired signal frequencies with no insertion loss or distortion, and completely block all signals in the stop-band, real filters have DC and AC resistances that contribute to insertion loss, requiring careful component selection. Passive electronic LC filters block, or reduce, noise (EMI) from circuits and systems, and separate, or condition, desired signals. Example: Low-Pass LC Filter Schematic What is an LC Filter?Īn LC filter combines inductors (L) and capacitors (C) to form low-pass, high-pass, multiplexer, band-pass, or band-reject filtering in radio frequency (RF) and many other applications.
0 kommentar(er)
