LTC3769 start-up problems

Dear EngineerZone-team,

I have built a small board to evaluate the LTC3769 as a synchronous 12V to 60V boost converter. My circuit seems to have problems starting up - it stays in a hiccup mode with a re-try period of about 200ms. I have attached my schematics - did I do something obviously wrong?

Also, INTC_CC is at 6V, rather than the 5.4V quoted in the data sheet. The voltage at VFB never reaches 1.2V.

I have experimented with different output loads, different output capacitances and more soft-start capacitance - all with no effect.

Any advice would be much appreciated,

Best regards.

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