The key differences between the LM27403 and the TPS family are that the TPS parts have a fixed frequency while the LM27403/2 operates over an adjustable switching frequency range, which provides the customer more flexibility. The smaller min on-time of the LM27403 also provides the advantage of smaller duty cycles that enable high step down ratios. The LM27403 also has an advantage over the LM27402 and the TPS family in terms of current sense. The LM27402 uses inductor DCR sensing and the TPS family uses Rds(on) sensing, but the LM27403 adds a small BJT to the inductor DCR sensing, which adds temperature compensation. While the Rds(on) solution may be more familiar, it can have a wider variation in efficiency (up to 40% or higher). The DCR current sensing solves the efficiency dilemma while still providing a cost effective solution.