pwm ic uc 3844 problem

[abhay kulkarni]

ic 3844

I am working on a smps in which pwm ic uc 3844 is used.
As I switch on the power the pwm ic is getting shorted.i.e.pin no 2 of ic is internally getting shorted to in no. 5
This brings down vcc to ic at below 2 volts.
Why the ic is getting short
please explain

 

[Kripton2035]

3844 ic

hi
any schematic would help us to understand why it's getting shorted...
regards,

 

[abhay kulkarni]

relateddfserv.maxim-ic.com/en/an/an3844.pdf

the schematic is attched here with.