FUNCTIONAL DESCRIPTION

Function

Description

GENERAL

The TDA7372A is a quad channel single package audio power amplifier intended to reduce the

mismatch in the electrical characteristics among the four different channels and to consistently

drop the external component count. It contains four non inverting stages capable to operate

down to 20dB gain so minimizing the output noise and optimizing SVR and distortion.

OUTPUT STAGE

The output stage is a single ended type suitable to drive 4

Ω loads. It consists of a class AB fully

complementary PNP/NPN stages short circuit protected.

A rail to rail output swing is achieved without need of boostrap capacitors. Moreover, the

external compensation is not necessary.

ST-BY

The device features a St-BY function which shuts down the internal bias generators when the

ST-BY input is low. In ST-BY mode the amplifier sinks a small current (in the range of few

µAs).

When the St-BY pin is high the IC becomes fully operational.

MUTE

A mute function is also provided. This reduces the gain of the input stage to a level effectively

eliminating any audio input influence on the output stage when the mute line is low. When the

mute line is high the normal input path is restored.

The device goes automatically into mute state when the supply voltage goes below the

minimum allowable value. This prevents pop noises whenever the battery voltage drops below

a fixed threshold. When the supply voltage rises to it nominal value the device recovers the play

THERMAL

PROTECTION

The Thermal protection principle involves two different steps

a) Soft thermal limitation

b) Shutdown

As long as the junction temperature remains below a preset threshold, the I.C. will deliver the

full power. Once the threshold has been reached, the device automatically goes into mute

status. The play to mute transition is internally controlled so producing a soft muting without

unpleasant effect. Supposing the junction temperature does not reduce to safe levels, a

complete shutdown will occur.

BUILT-IN SHORT

CIRCUIT

PROTECTION

A built-in protection circuit assures reliable and safe operation in presence of:

- AC short circuit to GND

The DC short protector acts in a way to avoid that the device is being turned on (by ST-BY)

Moreover, as the involved circuitry is normally disabled when a current higher than 5mA is fed

into the st-by pin, it is important, in order not to disable it, to have the external current source

driving the pin itself limited to 5mA. (figure 1 is shows the relevant waveforms).

Figure 15: Fault (DC short) waveforms

TDA7372A

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