LTC3729 model does not discharge RUN/SS cap

Question

The LTC3729 datasheet states that the if the output voltage falls below 70% then the RUN/SS pin will start discharge the softstart cap. I do not see this occur in the model when I apply a heavy step load to the output. The Run/SS pin never discharges even though I'm in a current limit and voltage has folded back well below 70%. I'm trying to better understand how this behaves to balance softstart time vs not latching off, but the model does not appear to work properly. 
 
 9151_5V_30A_3729_2phase.asc

mike.shriver · Accepted Answer

Hello, 
 I have confirmed that the RUN/SS pin in the LTC3729 LTspice model does not work correctly in regards to the over-current latch-off. The RUN/SS pin of the actual LTC3729 circuit does work as described in the data sheet. If the supply requires over-current latch-off, then the LTC3729 will provide this function. If not required, then over-ride the RUN/SS pin with a 5uA pullup as described in the data sheet. 
 Note, regardless of which method is used, drive the RUN//SS pin with an external UVLO comparator or logic to reset it when Vin goes low. This is shown below.

Best regards, 
 
 Mike)

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LTC3729 model does not discharge RUN/SS cap