LM1575/LM2575/LM2575HV SIMPLE SWITCHER® 1A Step-Down Voltage Regulator

FEATURES

• 3.3V, 5V, 12V, 15V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range,
  • 1.23V to 37V (57V for HV Version) ±4% Max Over
  • Line and Load Conditions
• Specified 1A Output Current
• Wide Input Voltage Range, 40V up to 60V for HV Version
• Requires Only 4 External Components
• 52 kHz Fixed Frequency Internal Oscillator
• TTL Shutdown Capability, Low Power Standby Mode
• High Efficiency
• Uses Readily Available Standard Inductors
• Thermal Shutdown and Current Limit Protection
• P⁺ Product Enhancement Tested

APPLICATIONS

• Simple High-Efficiency Step-Down (Buck) Regulator
• Efficient Pre-Regulator for Linear Regulators
• On-Card Switching Regulators
• Positive to Negative Converter (Buck-Boost)

DESCRIPTION

The LM2575 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 1A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, 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 LM2575 series offers a high-efficiency replacement for popular three-terminal linear regulators. It substantially reduces the size of the heat sink, and in many cases no heat sink is required.

A standard series of inductors optimized for use with the LM2575 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies.

Other features include a specified ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring 50 μA (typical) standby current. The output switch includes cycle-by-cycle current limiting, as well as thermal shutdown for full protection under fault conditions.

ABSOLUTE MAXIMUM RATINGS ^(1)(2)(3)

(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 TI Sales Office/ Distributors for availability and specifications.

(3) Refer to RETS LM1575J for current revision of military RETS/SMD.

Typical Application

(Fixed Output Voltage Versions)

Pin numbers are for the TO-220 package.

Block Diagram and Typical Application

3.3V, R2 = 1.7k

5V, R2 = 3.1k

12V, R2 = 8.84k

15V, R2 = 11.3k

For ADJ. Version

R1 = Open, R2 = 0Ω

Pin numbers are for the TO-220 package.