AN10436 PHILIPS [NXP Semiconductors], AN10436 Datasheet - Page 29

• Manufacturer Part Number: AN10436
• Description: TDA8932B/33(B) Class-D audio amplifier
• Manufacturer: PHILIPS [NXP Semiconductors]

NXP Semiconductors
AN10436_1
Application note
3.5.2 Filter capacitor
3.5.3 Zobel damping network
Remark: Saturation will cause audio distortion and severe saturation might even damage
the device.
The inductor types listed below are recommended, based on audio and EMC
performance.
Table 5.
Remark: For EMC purposes, it is important that the inner layer (for a multiple layer
winding) is attached to the switching output to minimize electrical stray fields. The inner
layer (start of the winding) is indicated with a dot mark on the inductor. In this way the
outside layer acts like an electrical shielding for the inner layer attached to the output with
fast alternating voltages.
A film capacitor is the best choice for audio performance. However, in most cases a
ceramic SMD capacitor (NPO or X7R) will also give a satisfying performance. The voltage
rating of the filter capacitor should be 25 % higher than the maximum supply voltage V
an asymmetrical application. In a symmetrical application the voltage rating should be
25 % higher than the half the maximum supply voltage (V
A zobel network is recommended in every Class-D amplifier application to damp the filter
resonance (See in
behavior (L
Brand and type
TOKO 16RHBP leaded,
shielded
TOKO 11RHBP A7503CY
leaded, shielded
TOKO DS86C
B992AS SMD, shielded
Sagami 7311NA leaded,
shielded
Sagami 7E08N SMD,
shielded
Fig 26. Zobel damping network
Recommended inductor types
E
) of the speaker voice coil.
Figure 26
Rev. 01 — 12 December 2007
L (μH)
22
47
22
47
22
47
22
47
22
47
R
V DD
V SS
Z
and C
I
4.9
3.4
2.21
1.60
2.0
1.4
3.4
2.3
2.6
1.8
sat
PWM
Z
). Filter resonance will occur due to the inductive
(A)
L LC
TDA8932B/33(B) Class-D audio amplifier
Output power (W per channel) in R
25
15
10
25
15
R Z
C Z
C LC
DDP
equivalent
voice coil
010aaa426
circuit
− V
L E
R E
SSP
).
AN10436
© NXP B.V. 2007. All rights reserved.
L
= 4 Ω
29 of 55
P
in