Hi, We are using the LT3757 controller in the SEPIC-Cuk topology to generate +/-15V at 400mA. Using the AN-1106, we have designed the circuit. In order the evaluate the stability of the controller, the AN-1106 uses the ridley's thesis formulae. The example calculation in AN-1106 uses ADP1612 controller's values for Vramp and Acs. Please let us know the values for Vramp and Acs for the LT3757 controller.
Thank You, Infant Jesuraj