Datasheet

Application information TDA2005
22/25 Doc ID 1451 Rev 6
4.1.7 Thermal shut-down
The presence of a thermal limiting circuit offers the following advantages:
1. an overload on the output (even if it is permanent), 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
that happens is that P
o
(and therefore P
tot
) and Id are reduced.
The maximum allowable power dissipation depends upon the size of the external heatsink
(i.e. its thermal resistance); Figure 37 shows the power dissipation as a function of ambient
temperature for different thermal resistance.
4.1.8 Loudspeaker protection
The circuit offers loudspeaker protection during short circuit for one wire to ground.
Figure 37. Maximum allowable power dissipa-
tion vs. ambient temperature
Figure 38. Output power and drain current vs.
case temperature (R
L
= 4 )
Figure 39. Output power and drain current vs.
case temperature (R
L
= 3.2 )
'!0'03
0
TOT
7







4
AMB
#






2
TH
#7
2
TH
#7
2
TH
#7
).&).)4%(%!43).+
'!0'03
0
O
7
4
CASE
#








    
)
D
!
)
D
0
O
6
3
6
2
,
7
FK(Z
'!0'03
0
O
7
4
CASE
#








    
)
D
!
)
D
0
O
6
3
6
2
,
7
FK(Z