I am trying to make a Buck Driver (More Info). While Building up the circuit and testing it seems to draw too much current. The NCP3420 was getting warm.
After Removing it and only connecting the VCC and GND to my bench power supply set to 8v 70ma it goes into cc-mode at about 5.1v. Is it broken?
Also is this the correct orientation?
Yes, assuming you have Vcc and GND hooked up as shown and they are the correct polarity and voltage (as you say they are) the part is likely broken and not meeting the datasheet spec:
Regardless of the state of the output enable, if the output is disconnected the part should draw no more than about 6mA. The datasheet condition specifies that the BST voltage is 12V, but I don't believe that can make the current any lower than spec, likely the reverse.
You might try grounding the logic inputs on the off chance that the part is oscillating and drawing excess current. (It's never a good idea to leave high impedance inputs floating.)
After breaking 2 ic's I decided to test the circuit with the load attached instead of not and the 3rd ic seems to still work.
Update- After breaking the 3 ic I realized there is no internal pull down on the IN pin and so if the IN floats with OD HIGH It breaks.