TPS546C23: Calculate the Effective IC Junction-to-Ambient Thermal Resistance

Hi Kapil,

Please refer to this app note for calculating the thermal resistance: www.ti.com/lit/an/spra953c/spra953c.pdf

In this case, 12.4°C/W of thermal resistance is calculated based on this equation:

RθJA = (TJ - TA) / Power = (100.08°C - 85°C) / 1.22W = 12.4°C/W

Hi Kapil,

We either simulate or measure the Theta JA values (JEDEC standard Theta JA and/or EVM Theta JA) and list them in the datasheet under the "Thermal Information" section. The WEBENCH uses the values straight from the datasheet.

The WEBENCH calculates the TJ value (the IC junction temperature) based on the ambient temperature, the IC power dissipation, and the Theta JA, using the abovementioned equation.

Hi Tomoya,

Thanks.