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INTEGRATED CIRCUITS
DATA SHEET
TDA7056AT 3 W mono BTL audio amplifier with DC volume control
Product specification
1998 Feb 23
NXP Semiconductors
3 W mono BTL audio amplifier with DC volume control
Product specification
TDA7056AT
FEATURES
• DC volume control • Few external components • Mute mode • Thermal protection • Short-circuit proof • No switch-on or switch-off clicks • Good overall stability • Low power consumption • Low HF radiation • ESD protected on all pins.
GENERAL DESCRIPTION
The TDA7056AT is a mono Bridge-Tied Load (BTL) output amplifier with DC volume control. It is designed for use in TVs and monitors, but is also suitable for battery-fed portable recorders and radios. The device is contained in a 20-lead small outline package.
A Missing Current Limiter (MCL) is built in. The MCL circuit is activated when the difference in current between the output terminal of each amplifier exceeds 100 mA (300 mA typ.). This level of 100 mA allows for Single-Ended (SE) headphone applications.
QUICK REFERENCE DATA
SYMBOL
VP Po Gv(max) ΔGv Iq(tot) THD
PARAMETER supply voltage output power maximum total voltage gain voltage gain control range total quiescent current total harmonic distortion
CONDITIONS
VP = 12 V; RL = 16 Ω VP = 12 V; RL = 16 Ω
VP = 12 V; RL = ∞ Po = 0.5 W
MIN.
4.5 3 34.5 75 − −
TYP. − 3.5 35.5 80 8 0.3
MAX.
18 − 36.5 − 16 1
UNIT V W dB dB mA %
ORDERING INFORMATION
TYPE NUMBER
TDA7056AT
NAME SO20
PACKAGE DESCRIPTION plastic small outline package with 20 leads; body width 7.5 mm
VERSION SOT163-1
1998 Feb 23
2
NXP Semiconductors
3 W mono BTL audio amplifier with DC volume control
BLOCK DIAGRAM
Product specification
TDA7056AT
handbook, full pagewidth
positive input DC volume control
n.c. VP
1 to 3, 8 to 13, 16, 18 to 20
4
TDA7056AT
5
7+ −
I+i
I−i
+ Vref STABILIZER
TEMPERATURE PROTECTION
14 + positive output 17 −
negative output
6 15
MGM576
signal power ground ground
Fig.1 Block diagram.
1998 Feb 23
3
NXP Semiconductors
3 W mono BTL audio amplifier with DC volume control
Product specification
TDA7056AT
PINNING
SYMBOL n.c. n.c. n.c. VP VI GND1 VC n.c. n.c. n.c. n.c. n.c. n.c. OUT+ GND2 n.c. OUT− n.c. n.c. n.c.
PIN DESCRIPTION
1 not connected 2 not connected 3 not connected 4 positive supply voltage 5 positive input 6 signal ground 7 DC volume control 8 not connected 9 not connected 10 not connected 11 not connected 12 not connected 13 not connected 14 positive output 15 power ground 16 not connected 17 negative output 18 not connected 19 not connected 20 not connected
handbook, halfpage
n.c. 1
20 n.c.
n.c. 2
19 n.c.
n.c. 3
18 n.c.
VP 4
17 OUT−
VI 5
16 n.c.
TDA7056AT
GND1 6
15 GND2
VC 7
14 OUT+
n.c. 8
13 n.c.
n.c. 9
12 n.c.
n.c. 10
11 n.c.
MGM577
Fig.2 Pin configuration.
1998 Feb 23
4
NXP Semiconductors
3 W mono BTL audio amplifier with DC volume control
Product specification
TDA7056AT
FUNCTIONAL DESCRIPTION
The TDA7056AT is a mono BTL output amplifier with DC volume control. It is designed for use in TVs and monitors 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 TDA7056AT 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 also 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 35.5 dB. The DC volume control stage has a logarithmic control characteristic.
The total gain can be controlled from +35.5 to −44 dB.
If the DC volume control voltage is below 0.3 V, the device switches to the mute mode.
The amplifier is short-circuit proof 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. 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 60 K/W. Therefore Tamb(max) = 150 − 60 × 1.8 = 42 °C.
LIMITING VALUES In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL
VP V5, 7 IORM IOSM Ptot Tamb Tstg Tvj tsc
PARAMETER supply voltage input voltage pins 5 and 7 repetitive peak output current non-repet.