LM25117: Unable to get more than 7.8A before shutdown.

Part Number:LM25117

I am trying to get at least 12V/12A out of the LM25117 device, but, whatever I try I reach 7.8A and then the device shuts down!!!

This is using a 6.8uH inductor.and I have tried 12uH and 3uH variations. They all seem to reach 7.8A and then turn of.

I am using an electronic DC load connected on the output, so am able to accurately apply the load.

The design is that used in the Webench tool.

Any assistance greatfully received.

Thanks.