The maximum voltage of the MAX15059 can reach 76V since the device operates in discontinuous conduction mode (DCM). In DCM, the relationship between the input voltage and the output voltage is not specified by Vo/Vi=1/1-D. In addition to the duty cycle and input voltage, the output voltage is also related to the inductance, the period, and the size of the load. Therefore, the maximum output voltage of the MAX15059 can reach 76V.
The relationship between the input voltage and the output voltage in DCM is:
where 
