L6932
Figure 10. Thermal Impedance
Considering a pulse duration of 1sec, the thermal impedance is close to 20°C/W, allowing much bigger power
dissipated.
Example:
Vin = 3.3V
Vout = 1.8V
Iout = 2A
Pulse Duration = 1sec
The power dissipated by the device is:
PDISS = (VIN - VOUT) · IOUT = 1.5 · 2 3W
Considering a thermal impedance of 20°C/W, the maximum junction temperature will be:
TJ = TA + ZTHJA · PDISS = 60 + 60 = 120°C
Obviously, with pulse durations longer than approximately 10sec the thermal impedance is very close to the
thermal resistance (60°C/W to 70°C/W).
8/10