SNVSBJ0A December 2019 – June 2020 LM5170
The internal 25-µA current source and a single external resistor RIPK establishes a voltage at the IPK pin to program the cycle-by-cycle current limit threshold. To set the inductor peak current limit value to IPK, RIPK should satisfy Equation 13:
IPK should be greater than the inductor peak current at full load, and lower than the inductor’s rated saturation current Isat.
Note that when the IPK pin voltage is greater than 4.5 V, either owing to a very large RIPK value or the pin being open or some other reason, an internal monitor circuit will shut down the switching, preventing the LM5170 from operating with erroneous peak current limit threshold.