Square Wave Shaper With Filter Characteristics to Reduce EMI and Passive Component Count

Filters and pulse shapers are widely used to reduce Electromagnetic Interference (EMI) by shaping the signal waveform. As the order of filter increases so does the silicon area requirement, which becomes an issue specially for low frequency applications. This paper outlines a methodology to implement a square wave shaper which approximates low-pass filter (LPF) characteristics using squaring circuits, with the aim of reducing component count for significant gain in silicon area. The shaper is analyzed in comparison to an ideal Bessel LPF and resulting differences are presented. Lastly, area savings are estimated and an outline of possible implementation of the shaper on schematic is presented.