TDA8933B NXP Semiconductors, TDA8933B Datasheet - Page 25

• Manufacturer Part Number: TDA8933B
• Description: The TDA8933B is a high-efficiency class D amplifier with low power dissipation
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDA8933B_1
Preliminary data sheet
14.4 Single-ended capacitor
14.5 Gain reduction
The SE capacitor forms a high-pass filter with the speaker impedance. This means that
the frequency response will roll off with 20 dB per decade below f
frequency of 3 dB.
The 3 dB cut-off frequency is equal to:
Where:
Table 15
40 Hz or 20 Hz 3 dB cut-off frequency.
Table 15.
The gain of the TDA8933B is internally fixed at 30 dB for SE and 36 dB for BTL. The gain
can be reduced by a resistive voltage divider at the input (see
When applying a resistive divider, the total voltage gain G
Equation 8
Where:
G
Impedance ( )
4
6
8
f
Fig 9.
–
•
•
•
•
•
•
v tot
3dB
f
R
C
G
G
R
3dB
L
SE
EQ
v(tot)
v(cl)
=
= load resistance (W)
=
= single-ended capacitance (F); see
= equivalent resistance, R3 and Z
---------------------------------- -
2
shows an overview of the required SE capacitor values in the case of a 60 Hz,
= 3 dB cut-off frequency (Hz)
Input configuration for reducing gain
= closed-loop voltage gain, fixed at 30 dB for SE (dB)
G
= total voltage gain (dB)
SE capacitor values
and
v cl
R
1
L
+
Equation
20
C
log
SE
Rev. 01 — 23 October 2008
audio in
C
f
680
470
330
----------------------------------------- -
SE
R
3dB
9:
EQ
( F)
= 60 Hz
+
R
R1
EQ
+
R1
R2
R2
470 nF
470 nF
i
(
f
1000
680
470
Figure 32
3dB
= 40 Hz
R3
100
k
v(tot)
010aaa137
can be calculated using
Figure
Class D audio amplifier
3dB
TDA8933B
f
2200
1500
1000
3dB
9).
and a cut-off
© NXP B.V. 2008. All rights reserved.
= 20 Hz
25 of 42
(7)
(8)