LM2576T-ADJ Description
The LM2576T-ADJ is an adjustable step-down voltage regulator that efficiently converts a higher input voltage to a stable, lower output voltage. It operates using a switching regulator approach, where an internal switch rapidly alternates between on and off states. This switching action, combined with an external inductor and capacitors, smooths out the pulsating current to deliver a steady output voltage.
The output voltage is adjustable through a feedback mechanism involving external resistors. The feedback pin senses the output voltage and adjusts the duty cycle of the internal switch to maintain the desired voltage level. This design allows the LM2576T-ADJ to deliver up to 3A current with high efficiency, reducing heat dissipation and making it suitable for various power supply applications.
LM2576T-ADJ Pinout
Pin 1 (VIN): Input Voltage. This pin connects to the input power source that provides the voltage to be regulated.
Pin 2 (Output): Output Voltage. This pin delivers the regulated output voltage to the load.
Pin 3 (Ground): This pin is connected to the ground system and serves as the reference point for the voltage regulation.
Pin 4 (Feedback): This pin is used to set and adjust the output voltage through a feedback network. It is connected to a resistor divider network to regulate the output voltage.
Pin 5 (ON/OFF): On/Off Control. This pin controls the operation of the regulator. Applying a high voltage to this pin turns the regulator on, while a low voltage turns it off.
LM2576T-ADJ CAD Models
Symbol
Footprint
3D Model
LM2576T-ADJ Block Diagram
LM2576T-ADJ Typical Application
LM2576T-ADJ Specification
| Specification | Value |
| Input Voltage Range | 4V - 40V |
| Output Voltage Range | 1.23V - 37V |
| Output Current | 3A |
| Efficiency | 75% |
| Switching Frequency | 52 kHz |
| Dropout Voltage | 2V @ 3A |
| Line Regulation | ±0.2% |
| Load Regulation | ±1.0% |
| Thermal Overload Protection | Yes |
| Short-Circuit Protection | Yes |
| Package | TO-220-5 |
| Temperature Range | -40°C - 125°C |
LM2576T-ADJ Features
- 3.3 V, 5.0 V, 12 V, 15 V, and Adjustable Output Versions
- Adjustable Version Output Voltage Range, 1.23 to 37 V ±4% Maximum Over Line and Load Conditions
- Guaranteed 3.0 A Output Current
- Wide Input Voltage Range
- 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
LM2576T-ADJ Applications
Simple High−Efficiency Step−Down (Buck) Regulator
Efficient Pre−Regulator for Linear Regulators
On−Card Switching Regulators
Positive to Negative Converter (Buck−Boost)
Negative Step−Up Converters
Power Supply for Battery Chargers
LM2576T-ADJ Package
The LM2576T-ADJ comes in a TO-220-5 package, which features five leads and is designed for through-hole mounting on printed circuit boards. This package includes an integrated heat sink tab that enhances thermal management, allowing the device to efficiently dissipate heat and handle higher power loads. The pin configuration includes connections for input voltage (Vin), ground (GND), adjustment (Adj), output voltage (Vout), and a no-connect (NC) pin, which can also aid in additional thermal dissipation.
How to Use LM2576T-ADJ？
The LM2576T-ADJ is a versatile step-down switching regulator that can be used to generate a stable, regulated output voltage from a higher input voltage. To use the LM2576T-ADJ, you need to connect it to an appropriate input voltage source, a load, and some external components. These components include a feedback resistor network to set the output voltage, an inductor for energy storage, a capacitor for output filtering, and a diode for freewheeling current.
The LM2576T-ADJ is easy to use and requires minimal external components. You can find detailed application notes and circuit examples on the manufacturer's website that will guide you through the design process and help you choose the right components for your specific application.
FAQs
What are the recommended input and output capacitors for the LM2576T-ADJ?
The LM2576T-ADJ typically requires an input capacitor of 100 µF and an output capacitor of 220 µF to ensure stable operation and minimize noise.
How should I handle heat dissipation for the LM2576T-ADJ?
The LM2576T-ADJ comes in a TO-220-5 package with a large tab that should be attached to a heat sink or PCB for effective thermal management, especially when operating near maximum current limits.
Can the LM2576T-ADJ be used in parallel for higher current applications?
Using multiple LM2576T-ADJ regulators in parallel is generally not recommended due to potential issues with current sharing and regulation. For higher current needs, consider using a single higher-current regulator or implementing other current-sharing techniques.
