Datasheet

Thermal information STA540
16/25 Doc ID 13907 Rev 6
5.1.3 Calculations using music power
The thermal resistance value calculated in each of the two above examples specifies a
heatsink capable of sustaining the maximum dissipated power. Realistically, however, and
as explained in the Application Note (AN1965), the heatsink can be smaller when the
application is musical content.
When music power is considered the resulting dissipation is about 40% less than the
calculated maximum. Thus, smaller or cheaper heatsinks can be employed. The heatsink
thermal resistance values are modified as follows:
for example 5.1.1: 10.5 W - 40% = 6.3 W, thus giving R
th_c-amb
= 14° C/W,
for example 5.1.2: 21 W - 40% = 12.6 W, thus giving R
th_c-amb
= 6° C/W.