TDA2030

Thermal shutdown

Doc ID 1458 Rev 3

13/17

6

Thermal shutdown

The presence of a thermal limiting circuit offers the following advantages:

1.

An overload on the output (even if it is permanent), or an above limit ambient

2.

The heatsink can have a smaller factor of safety compared with that of a conventional

circuit. There is no possibility of device damage due to high junction temperature. If for

any reason, the junction temperature increases to 150°C, the thermal shutdown simply

reduces the power dissipation at the current consumption.

The maximum allowable power dissipation depends upon the size of the external heatsink

(i.e. its thermal resistance); Figure 25 shows this power dissipation as a function of ambient

temperature for different thermal resistances.

Figure 23.

Output power and drain current vs.

Figure 24.

Output power and drain current vs.