This application report provides the method of calculating the maximum output current of the TPS92630-Q1 device in exterior-lighting automotive applications. The junction-to-ambient thermal resistance (RθJA) of the TPS92630-Q1 device is the key parameter when calculating the maximum output current of the TPS92630-Q1 device. This application report provides a method about how to measure the RθJA of TPS92630-Q1 reference boards. The reference boards are fabricated with different copper thickness. A comparison table of both measured and simulated RθJA of different copper thickness is given in the report for correlation.