LM2596 SIMPLE SWITCHER® Power Converter 150 kHz 3A Step-Down Voltage Regulator General Description

The LM2596 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 3A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation†, and a fixed-frequency oscillator. The LM2596 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 5-lead TO-220 package with several different lead bend options, and a 5-lead TO-263 surface mount package. A standard series of inductors are available from several different manufacturers optimized for use with the LM2596 series. This feature greatly simplifies the design of switch-mode power supplies. Other features include a guaranteed ±4% tolerance on output voltage under specified 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 frequency reducing current limit for the output switch and an over temperature shutdown for complete protection under fault conditions.

Features

• 3.3V, 5V, 12V, and adjustable output versions
• Adjustable version output voltage range, 1.2V to 37V ±4% max over line and load conditions
• Available in TO-220 and TO-263 packages
• Guaranteed 3A output load current
• Input voltage range up to 40V
• Requires only 4 external components
• Excellent line and load regulation specifications
• 150 kHz fixed frequency internal oscillator
• TTL shutdown capability
• Low power standby mode, IQ typically 80 µA
• High efficiency
• Uses readily available standard inductors
• Thermal shutdown and current limit protection

Applications

• Simple high-efficiency step-down (buck) regulator
• On-card switching regulators
• Positive to negative converter