The LM2591HV series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 1-A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, and an adjustable output version. This series of switching regulators is similar to the LM2590HV, but without some of the supervisory and control features of the latter. Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation, improved line and load specifications, and a fixed-frequency oscillator. The LM2591HV operates at a switching frequency of 150 kHz, thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Available in a standard 5-pin package with several different lead bend options, and a 5-pin surface mount package. Other features include a specified ±4% tolerance on output voltage under all conditions of input voltage and output load conditions, and ±15% on the oscillator frequency. External shutdown is included, featuring typically 90-µA standby current. Self-protection features include a two stage current limit for the output switch and an over temperature shutdown for complete protection under fault conditions.