TDA7056B Просмотр технического описания (PDF) - Philips Electronics
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TDA7056B Datasheet PDF : 16 Pages
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Philips Semiconductors
5 W mono BTL audio amplifier with DC
volume control
Product specification
TDA7056B
FUNCTIONAL DESCRIPTION
The TDA7056B is a mono BTL output amplifier with DC
volume control, designed for use in TV and monitor but is
also suitable for battery-fed portable recorders and radios.
In conventional DC volume circuits the control or input
stage is AC coupled to the output stage via external
capacitors to keep the offset voltage low. In the TDA7056B
the DC volume control stage is integrated into the input
stage so that no coupling capacitors are required. With this
configuration, a low offset voltage is still maintained and
the minimum supply voltage remains low.
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.
Consequently, a reduced power supply with smaller
capacitors can be used which results in cost reductions.
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.
The maximum gain of the amplifier is fixed at 40.5 dB.
The DC volume control stage has a logarithmic control
characteristic. Therefore, the total gain can be controlled
from 40.5 dB to −33 dB. If the DC volume control voltage
falls below 0.4 V, the device will switch to the mute mode.
The amplifier is short-circuit proof to ground, VP and
across the load. Also a thermal protection circuit is
implemented. If the crystal temperature rises above
+150 °C the gain will be reduced, thereby reducing the
output power. Special attention is given to switch-on and
switch-off clicks, low HF radiation and a good overall
stability.
Power dissipation
Assume VP = 12 V; RL = 16 Ω.
The maximum sine wave dissipation is = 1.8 W.
The Rth vj-a of the package is 55 K/W.
Therefore Tamb (max) = 150 − 55 × 1.8 = 51 °C.
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL
PARAMETER
CONDITIONS
VP
V3, 5
IORM
IOSM
Ptot
Tamb
Tstg
Tvj
Tsc
supply voltage
input voltage pins 3 and 5
repetitive peak output current
non-repetitive peak output current
total power dissipation
operating ambient temperature
storage temperature
virtual junction temperature
short-circuit time
Tcase < 60 °C
THERMAL CHARACTERISTICS
SYMBOL
Rth j-a
Rth j-c
PARAMETER
thermal resistance from junction to ambient in free air
thermal resistance from junction to case
MIN.
−
−
−
−
−
−40
−55
−
−
MAX.
18
5
1.25
1.5
9
+85
+150
+150
1
UNIT
V
V
A
A
W
°C
°C
°C
h
VALUE
55
10
UNIT
K/W
K/W
1997 Aug 15
4
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