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Microchip Technology LM2576WU
- Part No.:
- LM2576WU
- Manufacturer:
- Microchip Technology
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2576WU.pdf
- Description:
- IC REG BUCK ADJ 3A TO263-5
- Quantity:
- Payment:
- Shipping:
Inventory:162
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Product details
Overview
LM2576WU from Micrel, Inc. is an adjustable 3A step-down (buck) switching regulator in TO-263-5 package, operating at a fixed 52kHz switching frequency with input voltage range of 4V to 40V and output voltage programmable from 1.23V to 37V. It delivers ±2% feedback voltage accuracy, includes thermal shutdown and cycle-by-cycle current limiting, and is used in on-card DC/DC conversion for industrial power supplies.
For engineers reviewing the LM2576WU datasheet, LM2576WU pinout, LM2576WU application, or LM2576WU equivalent, key selection considerations include guaranteed 3A output current, 82% typical efficiency at 12VIN/5VOUT/3A, ON/OFF control with <200µA standby current, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2576WU integrates a 3A NPN switch, 1.23V bandgap reference, error amplifier, 52kHz oscillator, and thermal/current protection circuitry. Its fixed-frequency PWM architecture uses internal frequency compensation and requires only four external components - inductor, catch diode, input capacitor, and output capacitor - to form a complete buck regulator.
Feedback is taken directly from the output via resistive divider to the FB pin, enabling precise regulation across line and load variations. The ON/OFF pin provides logic-level shutdown with VIH ≥ 2.2V and VIL ≤ 1.0V, reducing quiescent current to ≤200µA while maintaining full fault protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 3A continuous output current supports high-power embedded rails without external current boosting. |
| Input Voltage Range | 4V to 40V operation enables direct use with 12V/24V industrial buses and wide-range unregulated inputs. |
| Output Voltage Range | 1.23V to 37V programmable via external resistor divider - covers most intermediate rail requirements. |
| Switching Frequency | Fixed 52kHz oscillator simplifies EMI filtering and allows use of low-cost, high-saturation-current inductors. |
| Feedback Accuracy | ±2% feedback voltage tolerance ensures stable output regulation under varying temperature and load conditions. |
| Standby Current | <200µA shutdown current enables low-power system sleep modes without auxiliary regulators. |
| Protection Features | Integrated thermal shutdown and cycle-by-cycle current limiting eliminate need for external fault management circuitry. |
Pinout & Package
LM2576WU is housed in a surface-mount TO-263-5 (D2PAK) package with exposed thermal pad for enhanced heat dissipation. Pin 3 is internally connected to the die substrate and must be soldered to a large copper area for thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 – VIN | Power Input | Accepts 4V–40V unregulated DC; connects to input capacitor and catch diode anode. |
| 2 – OUTPUT | Switch Node | Drives inductor; carries high di/dt switching current - requires short, low-inductance PCB trace. |
| 3 – GND | Power Ground | Main return path for switch current and IC ground; tied to thermal pad for thermal conduction. |
| 4 – FEEDBACK | Voltage Sense | High-impedance input monitoring output via resistor divider; sets regulated output voltage. |
| 5 – ON/OFF | Enable Control | Logic-level shutdown pin; >2.2V enables regulation, <1.0V disables output and reduces IQ to <200µA. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 52kHz oscillator | Enables predictable EMI profile and eliminates need for external timing components. |
| Internal frequency compensation | Reduces design risk by eliminating external compensation network tuning. |
| Thermal shutdown + current limit | Provides autonomous fault recovery without external sensing or latch circuitry. |
| ON/OFF logic control | Supports microcontroller-driven power sequencing with minimal GPIO overhead. |
| TO-263-5 thermal pad | Allows 45°C/W junction-to-ambient thermal resistance with 1 in² copper pour - no heatsink required at 3A. |
Applications
| Industrial Motor Drive Power Supply | Programmable Logic Controller (PLC) I/O Module |
|---|---|
|
Use Scenario: Converts 24V bus to 5V/3.3V for digital I/O isolation and FPGA configuration. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, low-noise intermediate rail. Use Value: Delivers 3A output with 82% efficiency and built-in current limiting protects against shorted field wiring. |
Use Scenario: Powers analog sensor front-end and ADC reference in modular PLC backplane slots. IC Role / Device Role / Timing Role: Adjustable-output buck converter generating precision 2.5V or 3.3V rails. Use Value: ±2% feedback accuracy maintains ADC reference stability across temperature and load transients. |
| Telecom Remote Radio Unit (RRU) | Test & Measurement Equipment Power Stage |
|
Use Scenario: Steps down 48V telecom supply to 12V for RF amplifier bias and control logic. IC Role / Device Role / Timing Role: High-input-voltage buck regulator handling wide line variation (36–72V nominal). Use Value: 40V max input rating and thermal shutdown ensure reliability in outdoor cabinet environments. |
Use Scenario: Generates variable test voltages (1.23–37V) for device-under-test biasing in bench power supplies. IC Role / Device Role / Timing Role: Programmable output buck stage controlled via DAC-driven feedback divider. Use Value: Wide output range and stable 52kHz switching enable clean, low-ripple outputs for sensitive DUTs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576T-ADJ | TO-220-5 package; higher θJA (65°C/W vs. 45°C/W); same electrical specs. | Suitable for prototyping or low-volume through-hole assembly; less efficient thermal performance. | Select when manual soldering or socket-based evaluation is preferred over SMT production. |
| LM2596S-ADJ | Higher 150kHz switching frequency; lower 3A max output; different pinout and layout requirements. | Better suited for compact designs needing smaller inductors; not drop-in compatible. | Choose for space-constrained boards where 150kHz allows sub-10mm inductors - but requires new layout. |
Compared with LM2576T-ADJ, the LM2576WU offers superior thermal performance in SMT production; compared with LM2596S-ADJ, it trades higher-frequency size reduction for proven 52kHz EMI behavior and identical pinout across the LM2576 family.
Availability
LM2576WU is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controllers, telecom remote radio units, and test equipment requiring stable component supply with long-term lifecycle support.
Supply support for LM2576WU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Micrel, Inc. was a U.S.-based semiconductor company specializing in power management, analog, and mixed-signal ICs before its acquisition by Microchip Technology in 2015.
The LM2576 series was designed as a robust, easy-to-use replacement for linear regulators in medium-power DC/DC conversion - targeting industrial, telecom, and embedded systems where reliability and minimal external components were critical.
FAQ
What is the maximum input voltage rating for the LM2576WU?
The LM2576WU has an absolute maximum input voltage rating of 45V, with recommended continuous operation up to 40V. Exceeding 40V may trigger internal protection or reduce reliability. The LM2576WU is rated for 4V–40V input range per datasheet specifications, making it suitable for 24V and 36V industrial bus applications without derating.
Does the LM2576WU require an external compensation network?
No, the LM2576WU includes internal frequency compensation optimized for standard buck configurations using common inductor values. This eliminates the need for external compensation components and simplifies design validation. The LM2576WU achieves stable regulation with only four external parts: input capacitor, output capacitor, inductor, and feedback resistor divider.
Can the LM2576WU be used in negative-output (inverting) configurations?
Yes, the LM2576WU supports inverting buck-boost topology to generate negative output voltages from a positive input. The datasheet explicitly lists "Positive to negative converter (inverting Buck-Boost)" as a typical application. The LM2576WU's internal switch and feedback architecture allow this configuration with appropriate external component repositioning and grounding.
What is the thermal resistance (θJA) of the LM2576WU in standard layout?
The LM2576WU has a junction-to-ambient thermal resistance of 45°C/W when mounted on a PCB with approximately 1 in² of copper surrounding the leads and thermal pad. This value assumes proper soldering of the exposed pad and is significantly better than the TO-220 version (65°C/W), enabling full 3A operation without a heatsink in many industrial layouts.
How does the ON/OFF pin function on the LM2576WU?
The ON/OFF pin on the LM2576WU provides logic-level enable/disable control: applying ≥2.2V enables regulation, while ≤1.0V disables the output and reduces quiescent current to ≤200µA. The LM2576WU retains full thermal and current protection during shutdown, and resumes regulation immediately upon re-enabling - supporting safe, software-controlled power sequencing.
LM2576WU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 3A
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263-5
LM2576WU FAQ
1.How can I place an order for LM2576WU through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576WU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM2576WU reliable?
The price and inventory of LM2576WU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576WU is usually 5 days.
3.What payment methods are accepted for LM2576WU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576WU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576WU?
LM2576WU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576WU order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM2576WU?
For technical support, including LM2576WU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576WU requirements.
6.How does Aetrix verify that LM2576WU is sourced from the original manufacturer or authorized distributors?
All LM2576WU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM2576WU meets industry standards.
7.What is the process for return or replacement of LM2576WU?
All LM2576WU units undergo pre-shipment inspection (PSI). If there is an issue with LM2576WU, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM2576WU part is unused and in its original packaging.
Return procedure for LM2576WU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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