There are a number of ways generate the required ripple. The easiest way is to add a resistor, as shown in this slide, in series with the output capacitor. TI generally recommends something on the order of about 25 mV of ripple at the feedback pin. In the case of the LM5017, the feedback pin voltage is compared to the band gap voltage of 1.25 V. With a 10 V output, there is an 8:1 ratio with the resistor divider. The result is eight times the amount of ripple on the actual output voltage. In this example there would be 200 mV of output ripple which is not really desirable but simple, inexpensive, and easy to implement.