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Microchip Technology LM2576-3.3WT
- Part No.:
- LM2576-3.3WT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
LM2576-3.3WT.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,556
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Product details
Overview
LM2576-3.3WT from Micrel is a fixed-output 3.3V, 3A step-down (buck) switching regulator in TO-220-5 package, featuring 52kHz fixed-frequency operation, ±3% output voltage tolerance over line/load, and integrated thermal shutdown and cycle-by-cycle current limiting. It replaces linear regulators in industrial power supplies requiring high efficiency and minimal heatsink area.
For engineers reviewing the LM2576-3.3WT datasheet, LM2576-3.3WT pinout, LM2576-3.3WT application, or LM2576-3.3WT equivalent, key selection criteria include input voltage range (4–40V), guaranteed 3A output capability, standby current <200µA, and compatibility with standard off-the-shelf inductors for rapid design implementation.
Technical Context
The LM2576-3.3WT integrates a 52kHz oscillator, error amplifier, bandgap reference (1.23V), PWM comparator, and 3A NPN switch with built-in current limit and thermal shutdown. Its feedback loop uses an internal 1.23V reference to regulate the fixed 3.3V output without external resistors.
It operates in continuous conduction mode with duty cycle up to 98%, supports ON/OFF control via pin 5 (logic-high disable, <200µA standby), and maintains regulation across input voltages from 6V to 40V at full 3A load - with dropout voltage as low as ~1.8V at 3A and 25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% over full temperature and load range - eliminates need for external feedback divider and ensures stable rail for 3.3V logic systems. |
| Max Output Current | 3A DC - supports mid-power applications such as FPGA core rails or microcontroller subsystems without external current boosting. |
| Input Voltage Range | 4V to 40V - enables direct use with unregulated 12V/24V industrial bus, automotive battery (with transient protection), or wide-range DC inputs. |
| Switching Frequency | 52kHz ±10% - allows use of low-cost, high-saturation-current toroidal or drum-core inductors (e.g., 330µH) with minimal EMI filtering. |
| Efficiency | 75% at VIN=12V, IOUT=3A - reduces thermal load vs. linear regulators; enables operation without heatsink at moderate ambient temperatures. |
| Standby Current | <200µA when ON/OFF pin = high - supports low-power sleep modes in battery-backed or energy-conscious systems. |
| Protections | Thermal shutdown + cycle-by-cycle current limiting - prevents damage during short-circuit, overload, or inadequate heatsinking conditions. |
Pinout & Package
Package: TO-220-5 (vertical mount, no heatsink required for ≤1.5A at 25°C ambient; recommended heatsink for full 3A operation).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Unregulated input supply | Accepts 4–40V DC; requires ≥100µF bulk input capacitance near pin to suppress switching transients. |
| 2 - OUTPUT | Regulated 3.3V output node | Drives 3A load; connects to catch diode anode and output capacitor; high di/dt node requiring short PCB trace. |
| 3 - GND | Power ground reference | Common return for input cap, output cap, and feedback network; must be single-point connected to minimize noise coupling. |
| 4 - FEEDBACK | Internal voltage sense input | Internally tied to 3.3V output - not accessible externally; unused in fixed-version parts like LM2576-3.3WT. |
| 5 - ON/OFF | Logic-controlled enable/disable | High (>2.2V) disables regulator (output off, IQ <200µA); low (<1.0V) enables operation; open-circuit defaults to ON. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output | Eliminates external resistor divider, reducing BOM count and layout sensitivity while guaranteeing ±3% accuracy across –40°C to +85°C. |
| Integrated 3A switch | Reduces external component count to only 4: input cap, output cap, catch diode, and inductor - enabling compact, cost-effective buck designs. |
| 52kHz fixed-frequency oscillator | Enables predictable EMI profile and simplifies filter design; avoids frequency jitter issues common in variable-frequency controllers. |
| ON/OFF logic control | Supports system-level power sequencing and standby modes without external MOSFETs or level shifters - compatible with 3.3V/5V logic. |
| Thermal + current protection | Self-protecting under fault conditions - no external circuitry needed for safe operation in harsh or unattended environments. |
Applications
| Industrial PLC Power Supply | Embedded Controller Core Rail |
|---|---|
|
Use Scenario: Providing clean 3.3V power to ARM Cortex-M4-based motion controllers in factory automation cabinets with 24V DC input. IC Role / Device Role / Timing Role: Primary buck regulator converting 24V bus to isolated 3.3V logic rail; operates continuously at 1.8A average load. Use Value: Delivers 75% efficiency and thermal shutdown protection - eliminating need for forced-air cooling and improving long-term reliability in sealed enclosures. |
Use Scenario: Powering FPGA configuration memory and I/O banks in edge AI gateways using 12V backplane input. IC Role / Device Role / Timing Role: Fixed-output DC/DC converter supplying regulated 3.3V with fast transient response to handle burst-mode logic loads. Use Value: Maintains ±3% output accuracy across –40°C to +85°C ambient, ensuring stable I/O voltage margins for high-speed serial interfaces (e.g., SPI, UART). |
| Automotive Body Control Module | Test Equipment Auxiliary Supply |
|
Use Scenario: Generating 3.3V for microcontroller and CAN transceiver in 12V vehicle body electronics, surviving load-dump transients. IC Role / Device Role / Timing Role: Input-stage buck regulator accepting 6–40V range; paired with TVS and input filter to meet ISO 7637-2 pulse requirements. Use Value: Withstands 40V max input and includes cycle-by-cycle current limiting - preventing latch-up during cold-crank or jump-start events. |
Use Scenario: On-board auxiliary supply for digital multimeter front-end ASICs requiring low-noise 3.3V from 15V internal rail. IC Role / Device Role / Timing Role: Pre-regulator stepping 15V down to 3.3V before LDO post-regulation; reduces LDO thermal dissipation by >60%. Use Value: Enables efficient pre-regulation with only four external components - accelerating prototyping and reducing test fixture BOM cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576-3.3T | Same electrical specs and TO-220-5 package, but non-RoHS compliant (lead-based solder finish); no "W" suffix. | Acceptable where RoHS exemption applies or legacy compliance is permitted; identical thermal and electrical behavior. | Select LM2576-3.3T only if RoHS compliance is not required and cost is prioritized over environmental certification. |
| MP1584EN-LF-Z | Higher 1.5MHz switching frequency, smaller external components, but lower 3A peak (2.5A continuous), and no integrated thermal shutdown flag. | Better suited for space-constrained designs; less robust under sustained overload or high-ambient conditions than LM2576-3.3WT. | Choose MP1584EN-LF-Z when board area is critical and load is ≤2A; retain LM2576-3.3WT for ruggedized 3A industrial use. |
Compared with LM2576-3.3T, the LM2576-3.3WT adds RoHS compliance without performance trade-offs; versus MP1584EN-LF-Z, it delivers higher continuous current, proven thermal resilience, and simpler magnetics - making it preferable for mission-critical 3A industrial power rails.
Availability
LM2576-3.3WT is available at Aetrix Electronics and suitable for industrial PLC power supplies, embedded controller core rails, and automotive body control modules requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.
Supply support for LM2576-3.3WT 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 analog and mixed-signal semiconductor company acquired by Microchip Technology in 2015; known for high-reliability power management and timing solutions.
The LM2576 series was designed as a drop-in, high-efficiency replacement for three-terminal linear regulators - targeting cost-sensitive, thermally constrained industrial and embedded power applications.
FAQ
What is the maximum input voltage rating for the LM2576-3.3WT?
The LM2576-3.3WT has an absolute maximum input voltage of 45V, with a recommended operating range of 4V to 40V. Operation above 40V risks exceeding internal transistor breakdown limits and is not guaranteed per datasheet specifications. For 48V systems, external clamping or pre-regulation is required before feeding the LM2576-3.3WT.
Does the LM2576-3.3WT require an external feedback resistor network?
No - the LM2576-3.3WT is a fixed-output variant with internal feedback set to 3.3V. Pin 4 (FEEDBACK) is internally connected and not accessible; no external resistors are needed. This distinguishes it from adjustable versions like LM2576-ADJ, which require R1/R2 to set VOUT.
Can the LM2576-3.3WT operate without a heatsink?
Yes, at reduced load and ambient temperature: the LM2576-3.3WT can deliver up to ~1.5A continuously without a heatsink at 25°C ambient (θJA ≈ 65°C/W). At full 3A, a minimum 10 cm² copper pour or small clip-on heatsink is required to maintain junction temperature below 125°C per thermal characterization data.
What type of catch diode is recommended for use with the LM2576-3.3WT?
A Schottky diode rated for ≥3A average current and ≥45V PIV is recommended - e.g., MBR360 (3A, 60V) or SB560 (5A, 60V). Fast recovery or standard PN diodes introduce excessive forward voltage drop and switching losses, degrading efficiency and thermal performance of the LM2576-3.3WT.
Is the LM2576-3.3WT pin-compatible with other LM2576 fixed-output variants?
Yes - all LM2576 fixed-output variants (e.g., LM2576-5.0WT, LM2576-12WT) share identical TO-220-5 pinout, thermal characteristics, and functional interface. Only the output voltage differs; external components (inductor, diode, capacitors) remain interchangeable across the family when adjusted for voltage/current requirements.
LM2576-3.3WT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-5
LM2576-3.3WT FAQ
1.How can I place an order for LM2576-3.3WT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576-3.3WT 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 LM2576-3.3WT reliable?
The price and inventory of LM2576-3.3WT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576-3.3WT is usually 5 days.
3.What payment methods are accepted for LM2576-3.3WT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576-3.3WT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576-3.3WT?
LM2576-3.3WT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576-3.3WT 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 LM2576-3.3WT?
For technical support, including LM2576-3.3WT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576-3.3WT requirements.
6.How does Aetrix verify that LM2576-3.3WT is sourced from the original manufacturer or authorized distributors?
All LM2576-3.3WT 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 LM2576-3.3WT meets industry standards.
7.What is the process for return or replacement of LM2576-3.3WT?
All LM2576-3.3WT units undergo pre-shipment inspection (PSI). If there is an issue with LM2576-3.3WT, 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 LM2576-3.3WT part is unused and in its original packaging.
Return procedure for LM2576-3.3WT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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