The efficiency for both EVMs peak at a load current of about 0.75 A and then decrease as the load current increases towards full load. Figure 2-1 shows the efficiency for the TPS5430EVM-173 at an ambient temperature of 25°C.

Figure 2-1 TPS5430 Efficiency

Figure 2-2 shows the efficiency for the TPS5431EVM-173 at an ambient temperature of 25°C.

Figure 2-2 TPS5431 Efficiency

The efficiency is lower at higher ambient temperatures, due to temperature variation in the drain-to-source resistance of the MOSFETs.