We selected TPS 61026 DRC, fixed 5.0V DC – DC converter for distribution of power in our student satellite EPS board. The converter failed (started drawing high current) when a load of 0.75A is applied during operation from a single lithium ion battery at an input voltage of 3.6V.
From the data sheet we understand that the power rating of this IC is 2.054W. The maximum permitted junction temperature is 150°C. The thermal resistance is θJA is 48.7 °C/W.
The power dissipation in the IC was around 940 milli watts. The thermal pad of the IC was directly soldered to our PCB. (connected to ground copper plane). The testing was performed in a clean A/C room with an ambient maintained at less than 25C.
AS per the data sheet the IC should not have failed. Kindly let us have an explanation for its failure?
Most failures of this IC are layout related. You need to follow the layout guidelines in the datasheet and copy the EVM's layout.