This is a 7-lead Plastic Small Outline Integrated Circuit (SOIC) Package from STMicroelectronics made for high speed logic applications such as CPU/system clock buffering, address comparators and data registers. It has a maximum operating temperature of 150 degrees Celsius. The pin designation is as follows: Pin 1 is CLK, Pin 2 is CLK In, Pin 3 is CLK Out, Pin 4 is GND, Pin 5 is VCC, Pin 6 is Output Enable, and Pin 7 is NC.