The LM5008ASD/NOPB is a constant on-time non-synchronous Buck Regulator for use with secondary high voltage post regulator. The functional differences of the LM5008A is the minimum input operating voltage is 6V, the on-time equation is slightly different and the requirement for a minimum load current is removed. The step-down switching regulator features all of the functions needed to implement an efficient, buck bias regulator. This high voltage regulator contains an 100V N-channel buck switch. 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 and VCC undervoltage lockout.
Internal start-up regulator
No loop compensation required
Ultrafast transient response
On time varies inversely with input voltage
Operating frequency remains constant with varying line voltage and load current
