TPS564247: Thermal Issue

Hi Deepak,

I will check in lab, give you feedback later.

Best Regards,

Zhou

Hi Deepak,

1. On the EVM board, I set the same Vout =2.8V as yours. Load = 2.5A, the chip temperature is 51 degrees Celsius (picture.1). This is to meet the design requirements

2. Yes, you can increase the copper area of the layout to increase the scattering.

3.I don't quite understand the meaning of the specific parameters in your calculation. Can you give more details?

                                                                                        picture.1

The below calculations are done with practical board to find the correct dissipation

n=efficiency

PD_total: Total power dissipation in the buck regulator

PD_IC: (PD_total- Inductor loss) gives the dissipation only in the IC excluding the inductor loss.

P_IC_s= just for mathcad calculation i have made it unitless.

If i assume your efficiency of 92% as per datasheet and 12V input, the power losses will be around 0.6.

So the temperature rise= 0.6*58C/W+25C=59 deg. (as per datasheet)

So your EVM might be having a very low RJA of about 43C/W.

Is it correct?

Correcting myself- above calculated 59 deg would be the junction temperature and case temperature is 51 as observed by you