DC/DC converters also have a limit to the minimum and maximum achievable output voltage. To approximate the minimum output voltage, it is necessary to know the minimum controllable on time of the DC/DC converter and its switching frequency. In this instance, the worst case minimum controllable on time is 200 nanoseconds and the frequency is fixed 500 kHz. Now, the minimum duty cycle can be calculated to be 0.1 or 10%. If the input voltage is 24V, the lowest output voltage would be 2.4V to avoid pulse skipping. Of course, the lowest output voltage cannot be set below the limitations of the 1.22 V internal reference. The upper output voltage limit is approximated by the maximum duty cycle. The TPS5430 datasheet shows the minimum worst case value to be 87%. With an input voltage of 24 V, the highest achievable output voltage is 20.8 V. Beware of competitors that do not specify the minimum controllable on time or the maximum duty cycle in the datasheet. If these output voltage values are critical, it’s better to find another DC/DC converter in the long run.