Philips TDA7057A Service Manual

INTEGRATED CIRCUITS

DATA SH EET

TDA7057AQ

2 x 5 W stereo BTL audio output
amplifier with DC volume control

Preliminary specification
Supersedes data of July 1994
File under Integrated Circuits, IC01

1995 Nov 08

Philips Semiconductors Preliminary specification

2 x 5 W stereo BTL audio output

TDA7057AQ

amplifier with DC volume control

FEATURES

• DC volume control

• Few external components

• Mute mode

• Thermal protection

• Short-circuit proof

• No switch-on and switch-off clicks

• Good overall stability

• Low power consumption

• Low HF radiation

• ESD protected on all pins.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

P

P

out

G

v

G

C

I

q(tot)

THD total harmonic distortion P

supply voltage 4.5 − 18 V
output power VP= 12 V; RL=16Ω 3.0 3.5 − W

V

P

voltage gain 39.5 40.5 41.5 dB
gain control 68 73.5 − dB
total quiescent current VP= 12 V; RL= ∞−22 25 mA

out

GENERAL DESCRIPTION

The TDA7057AQ is a stereo BTL output amplifier with DC
volume control. The device is designed for use in TV and
monitors, but are also suitable for battery-fed portable
recorders and radios.

Missing Current Limiter (MCL)

A MCL protection circuit is built-in. The MCL circuit is
activated when the difference in current between the
output terminal of each amplifier exceeds 100 mA
(typical 300 mA). This level of 100 mA allows for
headphone applications (single-ended).

= 12 V; RL=8Ω−5.3 − W

= 0.5 W − 0.3 1 %

ORDERING INFORMATION

TYPE

NUMBER

NAME DESCRIPTION VERSION

PACKAGE

TDA7057AQ DBS13P plastic DIL-bent-SIL power package; 13 leads (lead length 12 mm) SOT141-6

1995 Nov 08 2

Philips Semiconductors Preliminary specification

2 x 5 W stereo BTL audio output
amplifier with DC volume control

BLOCK DIAGRAM

handbook, full pagewidth

TDA7057AQ

input 1

DC volume

control 1

3

1

V

ref

STABILIZER

V

P

4

I i

Ι

I i

TEMPERATURE

PROTECTION

TDA7057AQ

13

positive
output 1

11

negative
output 1

input 2

DC volume

control 2

5

7

2

not

connected

I i

ΙΙ

I i

12

power

ground 1

signal

ground

6

Fig.1 Block diagram.

9

power

ground 2

negative

10

output 2

8

positive
output 2

MSA714

1995 Nov 08 3

Philips Semiconductors Preliminary specification

2 x 5 W stereo BTL audio output
amplifier with DC volume control

PINNING

SYMBOL PIN DESCRIPTION

VC1 1 DC volume control 1
n.c. 2 not connected
V

l (1)

V

P

V

l (2)

SGND 6 signal ground
VC2 7 DC volume control 2
OUT2+ 8 positive output 2
PGND2 9 power ground 2
OUT2− 10 negative output 2
OUT1− 11 negative output 1
PGND1 12 power ground 1
OUT1+ 13 positive output 1

3 voltage input 1
4 positive supply voltage
5 voltage input 2

handbook, halfpage

VC1

n.c.

V

I (1)

V

V

I (2)

SGND

VC2
OUT2
PGND2
OUT2
OUT1
PGND1
OUT1

P

1
2
3
4
5
6
7

TDA7057AQ

8

9
10
11
12
13

TDA7057AQ

MSA716

FUNCTIONAL DESCRIPTION

The TDA7057AQ is a stereo output amplifier with two DC
volume control stages. The device is designed for TV and
monitors, but are also suitable for battery-fed portable
recorders and radios.

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.

In the TDA7057AQ 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 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.

Fig.2 Pin configuration.

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 stages have 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 a short-circuit protected to ground, V

and

P

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.

1995 Nov 08 4

Philips Semiconductors Preliminary specification

2 x 5 W stereo BTL audio output

TDA7057AQ

amplifier with DC volume control

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134).

SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT

V

P

I

ORM

I

OSM

P

tot

T

amb

T

stg

T

vj

t

sc

V

n

THERMAL CHARACTERISTICS

SYMBOL PARAMETER VALUE UNIT

R

th j-a

R

th j-c

supply voltage − 18 V
repetitive peak output current − 1.25 A
non-repetitive peak output current − 1.5 A
total power dissipation T

< 60 °C − 22.5 W

case

operating ambient temperature −40 +85 °C
storage temperature −55 +150 °C
virtual junction temperature − +150 °C
short-circuit time − 1hr
input voltage pins 1, 3, 5 and 7 − 5V

thermal resistance from junction to ambient in free air 4 K/W
thermal resistance from junction to case 40 K/W

Power dissipation

Assume V
At T

amb (max)

R

th tot

R

th tot=Rth j-c+Rth c-hs+Rth hs

R

th c-hs+Rth hs

= 12 V and RL=16Ω. The maximum sine wave dissipation is 2 × 1.8 W = 3.6 W.

P

=60°C;

= (150 − 60)/3.6 = 25 K/W

=25−4 = 21 K/W

1995 Nov 08 5