The TPSM8287Axx module family consists of device variants with different switching frequencies. For available options see Table 4-1. The different switching frequencies allows the selection of the device which provides the best efficiency by optimizing the power losses for a given use case.

A lower switching frequency version does not necessarily offer a higher efficiency across the entire load, Vin or Vout range. The lower switching frequency does reduce the switching losses in the power stage, but at the same time leads to a higher ripple current in the inductor which leads to higher inductor losses, higher output voltage ripple, and a lower maximum output current (see Section 7.3.13). Because of this, TI recommends to compare the efficiency when picking a certain device variant.

Figure 7-14 and Figure 7-15 provide an efficiency comparison between the 1.5-MHz TPSM8287A12BAS and 2.25-MHz TPSM8287A12BBS. For output voltages ≥ 1.2 V, the efficiency between the 2.25-MHz and 1.5-MHz device is almost the same for high load currents, whereas the 2.25-MHz version gives higher efficiency at load currents below 3 A. The 1.5-MHz device generally gives higher efficiency for the other operating points, especially for lower output voltages. For output voltages >= 1.2 V, TI recommends the 2.25-MHz device for most applications due to the comparable efficiency, lower output voltage ripple, and higher maximum output current.

VIN = 3.3 V

TA = 25°C

FPWM

Figure 7-14 Efficiency Comparison TPSM8287A12BAS vs TPSM8287A12BBS

VIN = 5.0 V

TA = 25°C

FPWM

Figure 7-15 Efficiency Comparison TPSM8287A12BAS vs TPSM8287A12BBS