Lowpass Filter Has Improved Step Response

Abstract: Adding optimization circuitry to a lowpass filter allows the filter to adjust its cutoff frequency dynamically, preserving the step-response time for relatively low cutoff frequencies.
Maxim/Dallas > App Notes > AMPLIFIER AND COMPARATOR CIRCUITS FILTER CIRCUITS (ANALOG)

Keywords: lowpass filter, step response, time-domain response, signal conditioning, switched-capacitor filter, Apr 26, 2004
SC filter

APPLICATION NOTE 3203
Lowpass Filter Has Improved Step Response

Adding optimization circuitry to a lowpass filter allows the filter to adjust its cutoff frequency dynamically,
preserving the step-response time for relatively low cutoff frequencies.


A common problem when designing lowpass filters for signal conditioning is their effect on the system's time-
domain response. Because pushing the cutoff frequency lower slows the step response, the system may fail to
recognize significant changes in time.


The Figure 1 circuit allows lower cutoff frequencies