LPV324M National Semiconductor, LPV324M Datasheet - Page 12

• Manufacturer Part Number: LPV324M
• Description: General Purpose / Low Voltage / Low Power / Rail-to-Rail Output Operational Amplifiers
• Manufacturer: National Semiconductor

Application Notes
(Continued)
DS100920-14
FIGURE 9. Simple Low-Pass Active Filter
DS100920-15
FIGURE 10. Frequency Response of Simple Low-pass
Active Filter in Figure 9
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:
−6
SlewRate
0.5 x (
V
) X 10
V/µsec
H
OPP
Where
is the highest frequency of interest, and V
is
H
OPP
the output peak-to-peak voltage.
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