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Microchip Technology LM2576-3.3WU-TR
- Part No.:
- LM2576-3.3WU-TR
- Manufacturer:
- Microchip Technology
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2576-3.3WU-TR.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,790
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Product details
Overview
LM2576-3.3WU-TR from Micrel is a fixed-output 3.3V, 3A step-down (buck) switching regulator in TO-263-5 package, featuring 52kHz fixed-frequency operation, ±3% output voltage accuracy over line/load/temperature, thermal shutdown, cycle-by-cycle current limiting, and <200µA standby quiescent current. It replaces linear regulators in industrial power supplies requiring high efficiency and minimal heatsinking.
For engineers reviewing the LM2576-3.3WU-TR datasheet, LM2576-3.3WU-TR pinout, LM2576-3.3WU-TR application, or LM2576-3.3WU-TR equivalent, key selection criteria include guaranteed 3A output current, 4V–40V input range, 75% typical efficiency at 3A, TO-263 thermal performance, and ON/OFF control interface compatibility with microcontroller GPIOs.
Technical Context
The LM2576-3.3WU-TR integrates a 3A NPN switch, 52kHz oscillator, error amplifier with 1.23V internal reference, PWM comparator, and protection circuitry-including thermal shutdown and peak-current limiting-within a monolithic IC. Its fixed 3.3V output eliminates external feedback resistors, simplifying design versus adjustable variants.
It operates in continuous conduction mode with internal frequency compensation, requires only four external components (input capacitor, output capacitor, diode, inductor), and delivers stable regulation across –40°C to +85°C ambient while maintaining ≤3.366V max output under full load and 40V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% (3.168V–3.465V) over 0.5A–3A load and 6V–40V input ensures compatibility with 3.3V logic rails without trimming. |
| Max Output Current | Guaranteed 3A continuous output supports single-rail power for microcontrollers, FPGAs, and peripheral ICs without derating. |
| Input Voltage Range | 4V to 40V DC enables direct use with 12V/24V industrial buses, automotive batteries (with transient suppression), and unregulated wall adapters. |
| Switching Frequency | 52kHz ±10% (47–58kHz) allows use of low-cost, standard 330µH inductors and reduces EMI filtering complexity vs. MHz-range converters. |
| Efficiency | 75% typical at VIN=12V, IOUT=3A, VOUT=3.3V minimizes power loss and thermal stress-enabling operation without heatsink at moderate ambient temperatures. |
| Quiescent Current | <200µA in shutdown (ON/OFF pin high) enables ultra-low-power system-level sleep modes for battery-backed applications. |
| Protection Features | Integrated cycle-by-cycle current limiting and thermal shutdown prevent damage during overload, short-circuit, or elevated ambient conditions. |
Pinout & Package
LM2576-3.3WU-TR uses the 5-lead TO-263 (also known as D²PAK) surface-mount package with exposed thermal pad for enhanced heat dissipation. The package measures 10.16mm × 13.97mm × 4.50mm (L×W×H) and features gull-wing leads compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Power Input | Accepts 4V–40V unregulated DC; connects to bulk input capacitor (≥100µF) to suppress ripple and supply peak switch current. |
| 2 - OUTPUT | Switch Node | Drives external catch diode and inductor; carries high di/dt switching current-requires short, low-inductance PCB routing. |
| 3 - GND | Power Ground | Main return path for switch current and IC bias; must be tied directly to thermal pad and low-impedance ground plane. |
| 4 - FEEDBACK | Internal Reference Tap | Internally connected to 3.3V output; no external resistor network required-simplifies layout and improves stability. |
| 5 - ON/OFF | Enable Control | Logic-compatible shutdown input: ≤0.8V (max) turns device OFF (<200µA IQ); ≥2.2V (min) enables regulation. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V Output | Eliminates external feedback resistors-reduces BOM count, layout area, and potential drift from resistor tolerance/temperature. |
| 3A Integrated Switch | Monolithic NPN transistor rated for 3A continuous current avoids discrete MOSFET gate-drive complexity and layout sensitivity. |
| 52kHz Fixed Oscillator | Enables predictable EMI spectrum and use of off-the-shelf, low-DCR power inductors-no external timing components needed. |
| Thermal Shutdown | Activates at ~150°C junction temperature and latches off until cool-down-prevents permanent damage during sustained overload. |
| ON/OFF Logic Control | CMOS-compatible enable pin supports microcontroller-based power sequencing and system-level energy management without level shifters. |
Applications
| Industrial PLC I/O Modules | Embedded Controller Power Rails |
|---|---|
|
Use Scenario: Providing clean 3.3V power to isolated digital I/O circuits in programmable logic controllers operating from 24V DC field buses. IC Role / Device Role / Timing Role: Primary buck regulator converting 24V bus to regulated 3.3V for microcontroller peripherals and optocoupler drivers. Use Value: Delivers 3A headroom for multiple I/O channels, maintains ±3% output accuracy across wide temperature swings, and withstands 40V transients common in industrial environments. |
Use Scenario: Powering ARM Cortex-M or RISC-V SoCs and associated DDR memory interfaces in edge-computing gateways. IC Role / Device Role / Timing Role: Main system regulator supplying core logic voltage; synchronized via ON/OFF pin to processor sleep/wake states. Use Value: 75% efficiency at full load reduces thermal load on compact enclosures; TO-263 thermal pad enables reliable operation without heatsinks up to 65°C ambient. |
| Automotive Body Control Units | Point-of-Load Converters for Sensors |
|
Use Scenario: Generating 3.3V for CAN transceivers, LIN controllers, and LED drivers in 12V vehicle electrical systems. IC Role / Device Role / Timing Role: Secondary regulator downstream of main 5V rail or directly from battery (with input filtering). Use Value: Withstands cold-crank (4V) and load-dump (40V) conditions per ISO 7637-2; built-in current limiting protects against shorted sensor outputs. |
Use Scenario: Local 3.3V supply for precision analog sensors (e.g., pressure, temperature) in factory automation equipment. IC Role / Device Role / Timing Role: Low-noise point-of-load converter placed near sensor signal chain to minimize ground bounce and supply coupling. Use Value: Fixed 3.3V output eliminates resistor-divider errors; <200µA shutdown current extends battery life in portable diagnostic tools. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576-3.3WU-TRG | Same electrical specs and TO-263-5 package; RoHS-compliant with "hot-melting solder" exemption per original Micrel spec. | No functional difference; identical pinout, thermal profile, and reliability testing (100% burn-in). | Select when RoHS compliance documentation and traceability per M9999-082605-B revision are required. |
| LM2596-3.3 | Higher 150kHz switching frequency, lower 3A max current, different pinout (TO-220-5), and ±4% output tolerance. | Requires smaller inductor but higher EMI filtering; not drop-in due to pin mismatch and reduced thermal margin in TO-220. | Consider only if board redesign permits layout changes and higher-frequency EMI mitigation is acceptable. |
Compared with LM2576-3.3WU-TRG, the LM2576-3.3WU-TR offers identical performance but may lack updated RoHS certification records; versus LM2596-3.3, it provides superior thermal robustness in TO-263, tighter output tolerance, and proven 52kHz EMI behavior-critical for noise-sensitive industrial designs.
Availability
LM2576-3.3WU-TR is available at Aetrix Electronics and suitable for industrial PLCs, embedded controller power rails, automotive body control units, and point-of-load sensor supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2576-3.3WU-TR 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 RF solutions before its acquisition by Microchip Technology in 2015. Known for rugged, application-ready ICs with strong industrial qualification.
The LM2576 series was designed as a high-efficiency, drop-in replacement for linear regulators in cost-sensitive, thermally constrained 3A power conversion applications-emphasizing simplicity, reliability, and minimal external component count.
FAQ
What is the maximum input voltage rating for the LM2576-3.3WU-TR?
The LM2576-3.3WU-TR has an absolute maximum input voltage of 45V, with recommended continuous operation up to 40V. It is specified to deliver full 3A output across 6V–40V input range, making it suitable for 24V industrial systems and automotive applications with proper transient protection. Exceeding 40V risks exceeding thermal limits or triggering protection circuits.
Does the LM2576-3.3WU-TR require external feedback resistors?
No, the LM2576-3.3WU-TR does not require external feedback resistors. As a fixed-output variant, its internal feedback network is trimmed to 3.3V and connected directly to the FEEDBACK (pin 4) terminal. This eliminates resistor tolerance errors, temperature drift, and layout sensitivity-unlike adjustable versions such as LM2576ADJ.
What thermal performance can be expected from the LM2576-3.3WU-TR in TO-263 package?
The LM2576-3.3WU-TR in TO-263 (U) package has a junction-to-ambient thermal resistance (θJA) of 45°C/W with ~1 in² copper area, enabling operation up to +85°C ambient at full 3A load without a heatsink. The exposed thermal pad must be soldered to a solid copper pour for optimal performance-failure to do so degrades thermal capability significantly.
How does the ON/OFF pin of the LM2576-3.3WU-TR function in system-level power control?
The ON/OFF pin (pin 5) of the LM2576-3.3WU-TR provides logic-level enable/disable control: driving it below 0.8V disables regulation and reduces quiescent current to <200µA, while pulling it above 2.2V enables normal operation. This allows precise power sequencing with microcontrollers, FPGA configuration states, or system wake-up signals-without external MOSFETs or level shifters.
Is the LM2576-3.3WU-TR pin-compatible with other LM2576 variants in TO-263 package?
Yes, the LM2576-3.3WU-TR shares identical pinout, footprint, and thermal pad layout with all TO-263 variants in the LM2576 family-including LM2576-5.0WU, LM2576-12WU, and LM2576WU (adjustable). This enables board-level voltage flexibility: swapping the IC and input/output capacitors allows reuse of the same PCB for 3.3V, 5V, or 12V outputs.
LM2576-3.3WU-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- 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
LM2576-3.3WU-TR FAQ
1.How can I place an order for LM2576-3.3WU-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576-3.3WU-TR 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 LM2576-3.3WU-TR reliable?
The price and inventory of LM2576-3.3WU-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576-3.3WU-TR is usually 5 days.
3.What payment methods are accepted for LM2576-3.3WU-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576-3.3WU-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576-3.3WU-TR?
LM2576-3.3WU-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576-3.3WU-TR 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 LM2576-3.3WU-TR?
For technical support, including LM2576-3.3WU-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576-3.3WU-TR requirements.
6.How does Aetrix verify that LM2576-3.3WU-TR is sourced from the original manufacturer or authorized distributors?
All LM2576-3.3WU-TR 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 LM2576-3.3WU-TR meets industry standards.
7.What is the process for return or replacement of LM2576-3.3WU-TR?
All LM2576-3.3WU-TR units undergo pre-shipment inspection (PSI). If there is an issue with LM2576-3.3WU-TR, 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 LM2576-3.3WU-TR part is unused and in its original packaging.
Return procedure for LM2576-3.3WU-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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