The LM5009A is a functional variant of the LM5009 COT Buck Switching Regulator. The functional differences of the LM5009A are: The minimum input operating voltage is 6 volts, the on-time equation is slightly different, and the requirement for a minimum load current is removed. The LM5009A Step Down Switching Regulator features all of the functions needed to implement a low cost, efficient, Buck bias regulator. This high voltage regulator contains an 100 V N-Channel Buck Switch. The device is easy to implement and is provided in the MSOP-8 and the thermally enhanced LLP-8 packages. The regulator is based on a control scheme using an ON time inversely proportional to VIN. This feature allows the operating frequency to remain relatively constant. The control scheme requires no loop compensation. An intelligent current limit is implemented with forced OFF time, which is inversely proportional to Vout. This scheme ensures short circuit control while providing minimum foldback. Other features include: Thermal Shutdown, VCC under-voltage lockout, Gate drive under-voltage lockout, Max Duty Cycle limiter, and a pre-charge switch.