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

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
• Ensured 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, I_Q 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

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 ensured ±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. ⁽¹⁾

(1) † Patent Number 5,382,918.

Absolute Maximum Ratings ⁽¹⁾⁽²⁾

(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not ensure specific performance limits.

(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.

(3) The human body model is a 100 pF capacitor discharged through a 1.5k resistor into each pin.

Operating Conditions

Typical Application

(Fixed Output Voltage Versions)

Connection Diagrams

Figure 1. 5-Lead Bent and Staggered Leads, Through Hole TO-220 (T) Package

Figure 2. 5-Lead DDPAK/TO-263 (S) Package

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.