July 1994

4

Philips Semiconductors

Product specification

1 W BTL mono audio amplifier with DC

volume control

TDA7052A/AT

FUNCTIONAL DESCRIPTION

The TDA7052A/AT are mono BTL output amplifiers with

DC volume control, designed for use in TV and monitors

but 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 TDA7052A/AT the DC volume control stage is

integrated into the input stage so that no coupling

capacitors are required and yet a low offset voltage is

maintained. At the same time the minimum supply 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.

Thus a reduced power supply with smaller capacitors can

be used which results in cost savings.

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 dB to

−44 dB. If

the DC volume control voltage is below 0.3 V, the device

switches to the mute mode.

across the load. Also a thermal protection circuit is

implemented. If the crystal temperature rises above

+150

°C the gain will be reduced, so the output power is

reduced.

Special attention is given to switch on and off clicks, low

HF radiation and a good overall stability.

LIMITING VALUES

In accordance with the Absolute Maximum System (IEC 134)

SYMBOL

PARAMETER

CONDITIONS

MIN.

MAX.

UNIT

supply voltage range

−

18

V

repetitive peak output current

−

1.25

A

non-repetitive peak output current

−

1.5

A

total power dissipation

TDA7052A

−

1.25

W

TDA7052AT

−

0.8

W

operating ambient temperature range

−40

+85

°C

storage temperature range

−55

+150

°C

virtual junction temperature

−

+150

°C

short-circuit time

−

1hr

input voltage pin 2

−

8V

input voltage pin 4

−

8V