Application considerations for an instrumentation lowpass filter
The LTC1062 is a versatile, DC accurate, instrumentation lowpass filter with gain and phase that closely approximate a 5th order Butterworth filter. The LTC1062 is quite different from presently available lowpass switched-capacitor filters because it uses an external (R, C) to isolate the IC from the input signal DC path, thus providing DC accuracy. Figure 28.1 illustrates the architecture of the circuit. The output voltage is sensed through an internal buffer, then applied to an internal switched-capacitor network which drives the bottom plate of an external capacitor to form an input-to-output 5th order lowpass filter. The input and output appear ...