TDA8920B NXP Semiconductors, TDA8920B Datasheet - Page 16

• Manufacturer Part Number: TDA8920B
• Description: The TDA8920B is a high efficiency class-D audio power amplifier with very lowdissipation
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TDA8920B_2
Product data sheet
13.2 MODE pin
13.3 Output power estimation
13.4 External clock
For pop noise-free start-up an RC time-constant must be applied on the MODE pin. The
bias-current setting of the VI-converter input is directly related to the voltage on the MODE
pin. In turn the bias-current setting of the VI converters is directly related to the DC output
offset voltage. Thus a slow dV/dt on the MODE pin results in a slow dV/dt for the DC
output offset voltage, resulting in pop noise-free start-up. A time-constant of 500 ms is
sufficient to guarantee pop noise-free start-up (see also
The achievable output powers in several applications (SE and BTL) can be estimated
using the following expressions:
SE:
P
Maximum current (internally limited to 8 A):
BTL:
Maximum current (internally limited to 8 A):
Variables:
When using an external clock the following accuracy of the duty cycle of the external clock
has to be taken into account: 47.5 % < < 52.5 %.
I
P
I
o peak
o peak
o 1%
o 1%
R
f
t
V
P
P
P
osc
min
P
o(1%)
o(10%)
o(10%)
L
= load impedance
= single-sided supply voltage (so, if supply is 30 V symmetrical, then V
= oscillator frequency
= minimum pulse width (typically 150 ns)
=
=
= output power just at clipping
=
=
= output power at THD = 10 %
= 1.24
---------------------------------------------------------------------------------------- -
-------------------------------------------------------------------------------------------- -
------------------- -
R
V
----------------------------------------------------- -
2V
---------------------------------------------------------
------------------- -
R
L
L
P
R
R
P
+
+
L
L
0.4
0.8
1 t
R
R
P
1 t
–
L
L
o(1%)
–
+
Rev. 02 — 07 November 2005
V
min
+
2V
0.4
min
P
0.8
2
P
.
2
f
1 t
R
osc
R
f
1 t
L
–
osc
L
–
min
min
f
osc
f
osc
2
2
2
Figure
100 W class-D power amplifier
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
4,
5
TDA8920B
and 7).
P
= 30 V)
16 of 34
(1)
(2)
(3)
(4)