Descriptions: LM2575 Adjustable Voltage Regulator

The LM2575 series of regulators are monolithic integrated circuits ideally suited for easy and convenient design of a step−down switching regulator (buck converter). All circuits of this series are capable of driving a 1.0 A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5.0 V,12 V, 15 V, and an adjustable output version. These regulators were designed to minimize the number of external components to simplify the power supply design. Standard series of inductors optimized for use with the LM2575 are offered by several different inductor manufacturers. Since the LM2575 converter is a switch−mode power supply, its efficiency is significantly higher in comparison with popular three−terminal linear regulators, especially with higher input voltages. In many cases, the power dissipated by the LM2575 regulator is so low, that no heatsink is required or its size could be reduced dramatically. The LM2575 features include a guaranteed ±4% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency (±2% over 0°C to 125°C). External shutdown is included, featuring 80 A typical standby current. The output switch includes cycle−by−cycle current limiting, as well as thermal shutdown for full protection under fault conditions.

The LM2575 device greatly simplifies the design of switching power supplies by conveniently providing all the active functions needed for a step-down (buck) switching regulator in an integrated circuit. Accepting a wide input voltage range and available in an adjustable output version, the LM2575 has an integrated switch capable of delivering 1 A of load current, with excellent line and load regulation. The device also offers internal frequency compensation, a fixed-frequency oscillator, cycle-by-cycle current limiting, and thermal shutdown. In addition, a manual shutdown is available through an external ON/OFF pin.

The LM2575 represents a superior alternative to popular three-terminal linear regulators. Due to its high efficiency, it significantly reduces the size of the heat sink and, in many cases, no heat sink is required. Optimized for use with standard series of inductors available from several different manufacturers, the LM2575 greatly simplifies the design of switch-mode power supplies by requiring a minimal addition of only four to six external components for operation.

The LM2575 is characterized for operation over the virtual junction temperature range of –40°C to 125°C.

Features:

• 3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range of 1.23 V to 37 V ±4% Maximum Over Line and Load Conditions
• Guaranteed 1.0 A Output Current
• Wide Input Voltage Range: 4.75 V to 40 V
•  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
• Moisture Sensitivity Level (MSL) Equals 1
• Pb−Free Packages are Available

Specification:

• Maximum Supply Voltage : 45 V
• ON/OFF Pin Input Voltage:−0.3 V ≤ V ≤ +Vin V
• Output Voltage to Ground (Steady−State) : −1.0 V
• Power Dissipation: Internally Limited
• Thermal Resistance, Junction−to−Ambient:65 °C/W
• Thermal Resistance, Junction−to−Case : 5.0 °C/W
• Thermal Resistance, Junction−to−Ambient: 70 °C/W
• Thermal Resistance, Junction−to−Case : 5.0 °C/W
• Storage Temperature Range : −65 to +150 °C

Applications:

• Simple and High−Efficiency Step−Down (Buck) Regulators
• Efficient Pre−Regulator for Linear Regulators
• On−Card Switching Regulators
• Positive to Negative Converters (Buck−Boost)
• Negative Step−Up Converters
• Power Supply for Battery Chargers

Package Includes:

• 1x LM2575T LM2575 LM 2575 Adjustable Voltage Regulator Buck IC Max Input 40V Max Output 37V Step Down Single Phase Voltage Regulator IC 5 Pin TO-220-5 Package Switching Voltage Regulator