Philips Semiconductors
Product specification
Stereo BTL audio output amplifier with DC
volume control
TDA7053A
PINNING
SYMBOL
PIN
DESCRIPTION
not connected
n.c.
1
2
VC1
DC volume control 1
not connected
n.c.
3
n.c.
VC1
n.c.
1
2
3
4
5
6
7
8
16
OUT1
15 n.c.
14 PGND1
VI (1)
4
voltage input 1
VP
5
positive supply voltage
voltage input 2
VI (2)
6
V
13
12
I (1)
OUT1
OUT2
TDA7053A
TDA7053AT
SGND
VC2
7
signal ground
V
P
8
DC volume control 2
positive output 2
power ground 2
not connected
V
OUT2+
PGND2
n.c.
9
I (2)
11 n.c.
10
11
12
13
14
15
16
PGND2
SGND
VC2
10
9
OUT2
OUT2−
OUT1−
PGND1
n.c.
negative output 2
negative output 1
power ground 1
not connected
MSA719 - 2
Fig.2 Pin configuration.
OUT1+
positive output 1
For portable applications there is a trend to decrease the
supply voltage, resulting in a reduction of output power at
conventional output stages. Using the BTL principle
increases the output power.
FUNCTIONAL DESCRIPTION
The TDA7053A and TDA7053AT are stereo output
amplifiers with two DC volume control stages, designed for
TV and monitors, but also suitable for battery-fed portable
recorders and radios.
The maximum gain of the amplifier is fixed at 40.5 dB.
The DC volume control stages have a logarithmic control
characteristic. Therefore, the total gain can be controlled
from +40.5 to −33 dB.
In conventional DC volume control circuits the control or
input stage is AC coupled to the output stage via external
capacitors to keep the offset voltage low.
If the DC volume control voltage falls below 0.4 V, the
device will switch to the mute mode.
The two DC volume control stages are integrated into the
input stages so that no coupling capacitors are required
and a low offset voltage is still maintained. The minimum
supply voltage also remains low.
The amplifier is short-circuit protected to ground, VP and
across the load. A thermal protection circuit is also
implemented. If the crystal temperature rises above
150 °C the gain will be reduced, thereby reducing the
output power.
The BTL principle offers the following advantages:
• Lower peak value of the supply current
• The frequency of the ripple on the supply voltage is twice
the signal frequency.
Special attention is given to switch-on and switch-off
clicks, low HF radiation and a good overall stability.
Consequently, a reduced power supply with smaller
capacitors can be used which results in cost reductions.
1997 Jul 15
4
NXP [ NXP ]
