LM5164-Q1: Temperature operation

Hello,

The ambient temperature is going to reach 140 degrees C for 120 hours in total, the rest of the time the ambient temperature will be around 120 °C and the power consumption will be around 0.7W

Hello,

What are the input voltage, output voltage, and load current requirements during the 140degrees C and 120 degrees C operation?

We can do a rough calculation of the device temperature.

Thank you,
Katelyn

Hello,

For both 120 and 140 degrees C:

Input voltage 24-64

Output voltage 12

Load current 0.7

Hello,

For both 120 and 140 degrees C:

Input voltage 24-64 V, and nominal 48 V

Output voltage 12 V

Load current 0.7 A

Hello,

Using datasheet efficiency plots and using loss = (1-1/efficiency)*output power, I get a typical loss with 0.7 A and 64 V input of nearly 1 W. At hot, the RDS of the MOSFETs in the LM5164 will raise almost a factor of 2. Using 1.3 W of loss and an Rθjb (junction to board thermal resistnace) of 30.6 C/W, I get a temperature rise of nearly 40 degrees. While the part will not instantly be destroyed when above 150 C, we do not guarantee that TDS will not shut the part down if above this temperature.

In summary, 120 C ambient might work and 140 C will not work.

Regards, Robert