TPS2596: Purpose of D1/D2 in the datasheet schematic example

Hi Oba,

During events like short circuit the eFuse is forced to fast trip the internal FET fast to avoid damage to the down stream circuitry. As there is sudden change in current, the parasitic inductance at the input and output will cause over voltage at Vin and negative Voltgae at output respectively. These voltages can be above or below the recommended operating conditions of the IC and hence damage the IC.

To avoid damage to the IC during transient events, we generally recommend a TVS at the input to clamp for the input overvoltages and limit the negative voltage at the output by a Schottky diode.  Below image will help you in understanding this more.

As your operating voltage is 5V, the over voltage at the input may not be high enough to be above Absolute Maximum Rating of the device (21 V). In this case you can skip using a TVS at the input. We strictly recommend to thoroughly test the eFuse under all transient conditions to make sure that the over voltage at input is less than 21V and then skip using TVS at the input. 

The Schottky at the output may still be needed as the minimum voltage of 'Maximum Input Voltage Range'  is only -0.3V and it is easy for the parasitic inductance at output to create a negative voltage below -0.3V. In case in your testing you see the -ve voltage not going below -0.3V, you can avoid using Schottky diode as well.