I have a design that uses the LTC3406 switching regulator for both the 1.8V and 1.0V supplies for the G400S module but I am getting an issue with them where 1 or both thermal overload and the output fails. The thermal imaging camera shows them as hot at around 60°C and I then have to replace them.
They are using the standard parts that are recommended in the datasheet. GHI use similar parts on the G400D module. The current drawn by the CPU on these is way less than the 600mA they can produce at far less than 100mA.
Could it be that there is a delay required on the 1.8V and 1.0V supplies? On the G400D module pins 1 and 4 are not connected indicating that pin 1 (RUN input) is somehow connected to a delay circuit? There is no reference to this in the G400S datasheet for this requirement and the processor datasheet indicates some kind of sequencing but the timings are very small.