6.4.2
CS4525
Full-Bridge Output Filter (Stereo or Parallel)
Figure 27 shows the output filter for a full-bridge configuration. The transient-voltage suppression circuit
(snubber circuit) is comprised of a capacitor (680 pF) and a resistor (5.6 Ω, 1/8 W) on each output pin and
should be placed as close as possible to the corresponding PWM output pins to greatly reduce radiated
EMI. The inductors, L1, and capacitor, C1, comprise the low-pass filter. Along with the nominal load im-
pedance of the speaker, these values set the cutoff frequency of the filter. Table 20 shows the component
values based on nominal speaker (load) impedance for a corner frequency (-3 dB point) of approximately
35 kHz.
VP
OUTX+
680 pF
5.6 Ω
L1
*Diode is Rohm
RB160M-30 or
equivalent
C1
VP
L2
OUTX-
680 pF
5.6 Ω
Figure 27. Output Filter - Full-Bridge
Load
4Ω
6Ω
8Ω
L1, L2
10 µH
15 µH
22 µH
C1
1.0 µF
0.47 µF
0.47 µF
Table 20. Low-Pass Filter Components - Full-Bridge
60
DS726PP1