Buck Boost Converter LTC3113

Dear Sir/Madam,

We are using the LTC3113 Buck Boost for our application. We opted this IC for continuous 3A output current with 3.8V for one application and 5V for other application. During our testing what we observed is that the output voltage gradually drops and it is touching 0V at 700mA of output current. 

We are using regulated input power supply form 2.8V to 5.5V at 6A. We are able to attain output voltages of 3.8V and 5V without load. Here I am attaching you the image on how we connected the IC for 3.8V application. Please help us to find the solution.