LM2599

• 3.3-V, 5-V, 12-V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range: 1.2 V
  to 37 V ±4% Maximum Over Line and Load
  Conditions
• 3-A Output Current
• Available in 7-Pin TO-220 and TO-263 (Surface-
  Mount) Package
• Input Voltage Range Up to 40 V
• 150-kHz Fixed-Frequency Internal Oscillator
• Shutdown and Soft-Start
• Out-of-Regulation Error Flag
• Error Output Delay
• Low Power Standby Mode, I_Q, Typically 80 µA
• High Efficiency
• Uses Readily Available Standard Inductors
• Thermal Shutdown and Current-Limit Protection

The LM2599 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 3-A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, 12 V, and an adjustable output version.

The LM2598 is a member of the LM259x family, with additional supervisory and performance features added.

Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation, improved line and load specifications, fixed-frequency oscillator, Shutdown and Soft-start, error flag delay, and error flag output.

The LM2599 series 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 7-pin TO-220 package with several different lead bend options, and a 7-pin TO-263 surface-mount package.

A standard series of inductors (both through-hole and surface-mount types) are available from several different manufacturers optimized for use with the LM2599 series. This feature greatly simplifies the design of switch-mode power supplies.

Other features include a ±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 80-µA standby current. Self-protection features include a two stage current limit for the output switch and an overtemperature shutdown for complete protection under fault conditions.