Note that the single-op-amp active filters are used in to the

applications that require low quality factor, Q (

≤ 10), low fre-

quency (

≤ 5KHz), and low gain (≤ 10), or a small value for the

product of gain times Q (

≤ 100). The op amp should have an

open loop voltage gain at the highest frequency of interest at

least 50 times larger than the gain of the filter at this fre-

quency. In addition, the selected op amp should have a slew

rate that meets the following requirement:

SlewRate

≥ 0.5x(ω

Where

ω

the output peak-to-peak voltage.

DS100920-14

FIGURE 9. Simple Low-Pass Active Filter

DS100920-15

FIGURE 10. Frequency Response of Simple Low-pass

Active Filter in Figure 9

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