Other Parts Discussed in Thread: CSD17303Q5, CSD18512Q5B, CSD17305Q5A, CSD17306Q5A, CSD17577Q5A, CSD17576Q5B
I have a 160W dc-dc buck converter.
I'm using x2 CSD17573Q5B MOSFETs on a 160W dc-dc buck converter. The maximum input current can reach up to 9.5A.
My dc-dc converter has 94.5% efficiency while supplying 160W, it means that about 8.8W (160W*5.5%) drops on the MOSFETS (about 6.5W), inductor (about 1.3W) and sense resistors (about 1W).
I noticed that the MOSFETs temperature is rising up to 77c at room temperature (25c). As I wrote above, on each MOSFET there is about 3.2W.
In the datasheet of the CSD17573Q5B it is mention that RθJA Junction-to-ambient thermal resistance is 50 °C/W on an 1-in2 and 2-oz PCB plan.
As the above, on each MOSFET there is about 3.2W, and according to the datasheet the junction should get up to 3.2W*50c/W +25c = 185c.
My design has multiple layers but it seems that its not enough.
How can I cool down the MOSFETS more effective?
BTW, what is the recommended reliable junction temperature to work on for a long time?