This is the DC-DC converter: http://cds.linear.com/docs/en/datasheet/37911fb.pdf
There is a clockout pin in the chip and in the datasheet it says:
CLKOUT (Pin 33): Clock Output Pin. A 180° out-of-phase clock is provided at theoscillator frequency to allow for paralleling two devices for extending output power capability.
I searched in application notes and example designs but there were no use of this feature in them. I need a clear explanation of the working principle and how to do this.