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 Po (and therefore Ptot) 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 (RL = 4 )

Figure 39.

Output power and drain current vs.

case temperature (RL = 3.2 )