I downloaded the Pspice transient model and I configurated as the circuit that we are using. The circuit is configurated to the voltage output range of 15V-57V but when I set 0.98V to the TRK input I do not get more than 30V as output voltage.
I don’t know if there is a current limitation in the Pspice mode of the LM51231 or in the voltage source. I tried to edit them properties but I did not see any property related with the current.