The TPS6290x has extended the junction temperature to 150C vs. the 125C of the TPS621x0. This allows the device to be used at higher ambient temperatures with higher loads. With the 45C/W R_ӨJA of the TPS621x0, and with an ambient temperature of 100C, the device is allowed to dissipate only 550mW of power to reach the max junction temperature of 125C. Whereas, the TPS6290x, has more than 700mW of allowable power to dissipate before the max junction temperature of 150C is reached. This translates to how much load the device can deliver under the same ambient temperature, VIN, and VOUT condition.

For example, if we compare the two devices under 1MH switching frequency, 17-V input, 1.2-V output, and 100C ambient. The TPS62130 can deliver only approximately 2 A whereas the TPS6290X can deliver 3 A before the max junction temperature is reached. For the TPS621X0 to deliver full load of 3 A, the ambient temperature has to be reduced to 80C.