I use a TPS62163 (L: 2.2µH, Cout: 2x 10µF) to generate 5V for USB port from a 11.8V rail.
We got resports of some USB stick failing in the field after been used with this power.
I inspected one device ( and got 7.36V on the output instead of 5V, DCDC is switching +/- 3ms.
Adding a USB key (small current) doesn't change the output voltage.
At max current (add 10R power resistor for 500mA USB) the output voltage is 4.93V, switching is 50% 120ns pulses.
So at high load the output voltage is correct, but not at low and the device is switching and not totaly dead.
Any idea what can be the cause of this malfunction please ?