TDA7350A Datasheet, PDF (15/22 Pages) STMicroelectronics – 22W BRIDGE-STEREO AMPLIFIER FOR CAR RADIO

Load Dump Voltage Surge
The TDA 7350A has a circuit which enables it to
withstand a voltage pulse train on pin 9, of the
type shown in fig. 36.
If the supply voltage peaks to more than 40V,
then an LC filter must be inserted between the
supply and pin 9, in order to assure that the
pulses at pin 9 will be held within the limits
shown.
A suggested LC network is shown in fig. 35.
With this network, a train of pulses with amplitude
up to 120V and width of 2ms can be applied at
point A. This type of protection is ON when the
supply voltage (pulse or DC) exceeds 18V. For
this reason the maximum operating supply volt-
age is 18V.
Figure 35
Figure 36
TDA7350A
TDA7350A is 18V. However the device can with-
stand a DC voltage up to 28V with no damage.
This could occur during winter if two batteries are
series connected to crank the engine.
Thermal Shut-down
The presence of a thermal limiting circuit offers
the following advantages:
1)an overload on the output (even if it is perma-
nent), or an excessive ambient temperature
can be easily withstood.
2)the heatsink can have a smaller factor of
safety compared with that of a conventional
circuit. There is no device damage in the case
of excessive junction temperature: all hap-
pens is that Po (and therefore Ptot) and Id are
reduced.
The maximum allowable power dissipation de-
pends upon the size of the external heatsink (i.e.
its thermal resistance); Fig. 37 shows the dissipa-
ble power as a function of ambient temperature
for different thermal resistance.
Figure 37: Maximum Allowable Power
Dissipation vs. Ambient Temperature
Polarity Inversion
High current (up to 10A) can be handled by the
device with no damage for a longer period than
the blow-out time of a quick 2A fuse (normally
connected in series with the supply). This fea-
tures is added to avoid destruction, if during fitting
to the car, a mistake on the connection of the
supply is made.
Open Ground
When the radio is in the ON condition and the
ground is accidentally opened, a standard audio
amplifier will be damaged. On the TDA7350A pro-
tection diodes are included to avoid any damage.
Loudspeaker Protection
The TDA7350A guarantees safe operations even
for the loudspeaker in case of accidental shortcir-
cuit.
Whenever a single OUT to GND, OUT to V_S short
circuit occurs both the outputs are switched OFF
so limiting dangerous DC current flowing through
the loudspeaker.
Figure 38: Restart Circuit
DC Voltage
The maximum operating DC voltage for the
15/22