Z

LOAD

+

-

V

+

FREQUENCY (Hz)

10

0

-10

-20

-30

-40

1k

10k

100k

FILTER A

FILTER B

COMBINED

FILTER

B

kHz

k

nF

1

1.9

6.2

27

=

=

p ´

W ´

B

kHz

k

nF

1

1.6

6.2

33

=

=

p ´

W ´

B

R C

2

1

=

p

21

LMV841, LMV842, LMV844

LMV841-Q1, LMV842-Q1, LMV844-Q1

www.ti.com

SNOSAT1H – OCTOBER 2006 – REVISED JULY 2016

Product Folder Links: LMV841 LMV842 LMV844 LMV841-Q1 LMV842-Q1 LMV844-Q1

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Copyright © 2006–2016, Texas Instruments Incorporated

Typical Applications (continued)

(19)

For filter A, this gives Equation 20:

(20)

and Equation 21 for filter B:

(21)

8.2.1.3 Application Curve

The responses of filter A and filter B are shown as the thin lines in Figure 39; the response of the combined filter

is shown as the thick line. Shifting the center frequencies of the separate filters farther apart, results in a wider

band; however, positioning the center frequencies too far apart results in a less flat gain within the band. For

wider bands more band-pass filters can be cascaded.

Figure 39. Active Band-Pass Filter Curve

NOTE

Use the WEBENCH internet tools at www.ti.com for your filter application.

8.2.2 High-Side, Current-Sensing Circuit

Figure 40. High-Side, Current-Sensing Circuit