The TPS65631 and TPS65631W are popular devices for powering OLED displays in wearable applications. The displays used in these applications are quite small and consume much less current than the maximum the TPS65631/W devices can supply. Because of this, a number of customers have asked us if they can use a smaller inductor than the one specified in the TPS65631/W data sheets.
In applications where the TPS65631/W output current is low, the maximum inductor current actually occurs during start up, not during steady-state operation. This is because during start up the device has to charge up the output capacitance as well as supply the load.
If you want to use a smaller inductor, you must look at the peak inductor current during worst-case start-up conditions (minimum input voltage, maximum load, maximum output capacitance, etc.) and make sure your inductor is sized correctly. And don't forget to make sure that your final design includes suitable design margin and has been verified over temperature.
If you want to be on the safe side, or are not sure what you're doing, stick with the inductor recommended in the data sheet (or one similar). If you decide to go off-piste and use a smaller inductor, make sure you've thoroughly understood your application, because we can't help you much once you move away from the data sheet recommendations...