tda8944aj NXP Semiconductors, tda8944aj Datasheet - Page 5

• Manufacturer Part Number: tda8944aj
• Description: Tda8944aj 2 X 7 W Btl Audio Amplifier With Dc Gain Control
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 09433
Product data
8.2.1 Output power measurement
8.2.2 Headroom
8.2 Power amplifier
The input cut-off frequency is:
For R
As shown in
the switch-on delay during charging of the input capacitors can be minimized. This
results in a good low frequency response and good switch-on behaviour.
Remark: To prevent high frequency oscillations do not leave the inputs open, connect
a capacitor of 4.7 nF across the input pins close to the device (see
The power amplifier is a Bridge-Tied Load (BTL) amplifier with an all-NPN output
stage, capable of delivering a peak output current of 2 A.
The BTL principle offers the following advantages:
The output power as a function of the supply voltage is measured on the output pins
at THD = 10%; see
voltage of 12 V and the maximum available output current: 2 A repetitive peak
current.
Typical CD music requires at least 12 dB (factor 15.85) dynamic headroom -
compared to the average power output - for transferring the loudest parts without
distortion. At V
Average Listening Level (ALL) - music power - without any distortion yields:
The power dissipation can be derived from
respectively 12 dB headroom.
P
f
f
•
•
•
•
i cut off
i cut off
o ALL
Lower peak value of the supply current
The ripple frequency on the supply voltage is twice the signal frequency
No expensive DC-blocking capacitor
Good low frequency performance.
–
i
–
= 32 k and C
=
-------------
15.85
=
=
4 W
Equation
------------------------------------------
2
------------------------------------------------------------------------------
2
CC
=
0.5
0.5 32 10
= 12 V, R
Rev. 01 — 01 March 2002
252.4
Figure
1
i
= 220 nF:
R
2, large capacitors values for the inputs are not necessary; so
i
mW
C
10. The maximum output power is limited by the supply
L
1
i
= 8
3
220 10
2 x 7 W BTL audio amplifier with DC gain control
and P
9 –
o
= 4 W at THD = 0.2% (see
Figure 12 on page 11
=
45.2 Hz
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
TDA8944AJ
for 0 dB
Figure
Figure
15).
8), the
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