3.5

Thermal protection

Thermal protection acts when the junction temperature reaches 190 °C typical. At this point, the output of the IC

shuts down. As soon as the junction temperature falls below the thermal hysteresis value, the device starts

working again.

In order to calculate the maximum power that the device can dissipate, keeping the junction temperature below

the maximum operating value, the following formula is used:

PDMAX = (150 − TAMB) / Rthj-amb

Figure 20. Derating curve

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

-60

-40

-20

0

20

40

60

80

100

120

140

160

Ta [°C]

PWSSO12

DFN8

Rthj-amb = 28.4 °C/W

Rthj-amb = 32.5 °C/W

L99VR03

Applicationinformation

DS14803 - Rev 2

page 13/28