I am using the LTC3388-1 buck converter to provide a microcontroller with a regulated 1.8V voltage. I use pretty much the reference circuit as seen in the image.

When I disconnect the microcontroller (remove the wire CORE as seen in the image), I measure 1.8V in the output of the converter.

When I apply a resistor as load, the output voltage is again stable at 1.8V. As I decrease the resistance of the load resistor, the current increases, until it reaches 50mA (the maximum supported by LTC3388-1). Then, the voltage starts to drop.

So far so good.

When I connect the microcontroller (as seen in the image), I measure 0.6V at Vout. The current is also low at approximately 10uA; nowhere close the maximum limits of the converter.

What can possibly cause this voltage drop?

I am using the LTC3388-1 buck converter to provide a microcontroller with a regulated 1.8V voltage. I use pretty much the reference circuit as seen in the image.

When I disconnect the microcontroller (remove the wire CORE as seen in the image), I measure 1.8V in the output of the converter.

When I apply a resistor as load, the output voltage is again stable at 1.8V. As I decrease the resistance of the load resistor, the current increases, until it reaches 50mA (the maximum supported by LTC3388-1). Then, the voltage starts to drop.

So far so good.

When I connect the microcontroller (as seen in the image), I measure 0.6V at Vout. The current is also low at approximately 10uA; nowhere close the maximum limits of the converter.

Figure below shows the behaviour of the system when I connect the MCU.

What can possibly cause this voltage drop?