Thanks for your reply.
I thought 2msec shout down take places over the short circuit.
Is my understanding incorrect?
And one more, how can I estimate the limit output current? you said 550mA, but I don't know where this come from.
I'm planning to use this for Vin=5V, Vout=12V, Iout=0.01A .
Since output current is very low, so I want to selcect smaller and reasonable external compontens.
Best regards,
Tarzan