This chip is smokin' on a HDD control board for a 120GB Seagate Barracuda Model ST3120026A:
are the only markings I can see. No markings on the PCB to tell either. No polarity markings on pcb.
I plugged the atapi bridge - usb p/s cable in reverse momentarily and may have damaged the component. The strange part is it did not smoke when I had it plugged in backwards, only when I corrected it.