2.7V–19V input, 2A output — electronic fuse for the unregulated bus
The TPS259621DDAR is a Texas Instruments electronic fuse that sits between a DC supply rail and the load, replacing a PTC or a discrete fuse-and-MOSFET pair. It accepts an input from 2.7V up to 19V and delivers a continuous 2A output, with the current limit accuracy specified at ±10.4%.
That 125°C ceiling means the part can sit next to a motor driver or a hot power supply without derating the output current — the thermal pad on the 8-PowerSOIC package is the main path for pulling heat out of the die.
PowerPad layout — the copper pour under the part sets the thermal budget
The RθJA you achieve depends on that pad area; a 1-square-inch pour on a 2-layer board typically drops the junction temperature by 20–30°C compared to a minimal pad.
±10.4% current-limit accuracy — budget the tolerance in the load current
The ±10.4% accuracy on the current limit means the actual trip point for a nominal 2A setting could be as low as 1.79A or as high as 2.21A. A design drawing 1.8A steady-state is cutting it close — the load should stay at or below 1.6A to guarantee the fuse does not nuisance-trip across the tolerance band and temperature range.