AWR1843: Thermal Dissipation

Hello Long,

The average power consumption depends on the configuration used in the application. For typical usecase which configures the frames to have 20% chirp duty cycle and 2Tx at a time , the average power dissipation is about 1W. So without any additional heat sink , the thermal resistance with still air is  ~21 deg/W. That would mean you can reach a Ta of 104C.

To improve it better typically most customers incorporate a heat sink in their product design which contacts the top of the IC and distributes the heat out.

Regards,

Vivek

Hi Vivek,

Sorry for my late reply. Thank you very much for your answer - "without any additional heat sink means without taking in consideration of the 2500 sq.mil copper plane on the bottom layer of the EVM right?

For our application, we'd need to dissipate through balls and via to the bottom layer, a GND plane ~ (10 mm x 10 mm), through a non-conductive thermal pad prior to a big heatsink.

Does (21 deg/W) still apply in our application? And could we reduce this number further for each additional copper area added/appended to the GND plane above?

Kind regards,

Long

Hello Long,

Please find my reply below:

>> "without any additional heat sink means without taking in consideration of the 2500 sq.mil copper plane on the bottom layer of the EVM right?

I mean having additional metallic heat sink which would help absorb the heat from the device and dissipate it into the air.

>>For our application, we'd need to dissipate through balls and via to the bottom layer, a GND plane ~ (10 mm x 10 mm), through a non-conductive thermal pad >>prior to a big heatsink.

I would recommend using a conductive thermal pad (instead of non conductive) to enable better heat sinking.

>>Does (21 deg/W) still apply in our application? And could we reduce this number further for each additional copper area added/appended to the GND >>plane above?

If you have large number of GND vias (> 19 via with > 10mil drill) and multiple solid GND layers in the PCB , like the TI EVM , then this would apply to your board as well.

Regards,

Vivek