TDA7491MV Datasheet, PDF (24/28 Pages) STMicroelectronics – 25 W mono BTL class-D audio amplifier

Application information
TDA7491MV
7.6
Output low-pass filter
To avoid EMI problems, it may be necessary to use a low-pass filter before the speaker. The
cutoff frequency should be larger than 22 kHz and much lower than the output switching
frequency. It is necessary to choose the L-C component values depending on the loud
speaker impedance. Some typical values, which give a cut-off frequency of 27 kHz, are
shown in Figure 24 and Figure 25 below.
Figure 24. Typical LC filter for a 8-Ω speaker
Figure 25. Typical LC filter for a 4-Ω speaker
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Doc ID 14576 Rev 2