TDA2005 Datasheet, PDF (17/20 Pages) STMicroelectronics – 20W BRIDGE AMPLIFIER FOR CAR RADIO

TDA2005
BUILT-IN PROTECTION SYSTEMS
Load Dump Voltage Surge
The TDA2005 has a circuit which enables it to
withstanda voltagepulse train, on Pin 9, of the type
shown in Figure 34.
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 withing the limits shown.
A suggestedLC networkis shownin Figure33.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 voltage is 18V.
Figure 33
Figure 34
Open Ground
When the ratio is in the ON condition and the
ground is accidentally opened, a standard audio
amplifier will be damaged.On the TDA2005 protec-
tion diodes are included to avoid any damage.
Inductive Load
A protection diode is provided to allow use of the
TDA2005 with inductive loads.
DC Voltage
The maximum operating DC voltage for the
TDA2005 is 18V.
However the device can withstand a DC voltage up
to 28V with no damage. This could occur during
winter if twobatteries are series connectedto 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
p ermanent), o r 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 that
happens is that PO (and thereforePtot) and Id are
reduced.
The maximum allowable power dissipation de-
pends upon the size of the external heatsink(i.e. its
thermal resistance) ; Figure 35 shows the dissipa-
ble power as a function of ambient temperature for
different thermal resistance.
Loudspeaker Protection
The circuit offers loudspeaker protection during
short circuit for one wire to ground.
Short Circuit (AC and DC conditions)
TheTDA2005 can withstanda permanentshort-cir-
cuit on the output for a supply voltage up to 16V.
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 con-
nected in series with the supply). This feature is
added to avoid destruction, if during fitting to the
car, a mistake on the connection of the supply is
made.
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