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Microchip Technology LM2576-3.3BU TR
- Part No.:
- LM2576-3.3BU TR
- Manufacturer:
- Microchip Technology
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2576-3.3BU TR.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,430
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Product details
Overview
LM2576-3.3BU 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 tolerance over line/load/temperature, and integrated thermal shutdown and cycle-by-cycle current limiting. It replaces linear regulators in industrial power supplies requiring high efficiency and minimal external components.
For engineers reviewing the LM2576-3.3BU TR datasheet, LM2576-3.3BU TR pinout, LM2576-3.3BU TR application, or LM2576-3.3BU TR equivalent, key selection considerations include input voltage range (4–40V), guaranteed 3A output current, standby current <200µA, and compatibility with standard off-the-shelf inductors for rapid design implementation.
Technical Context
The LM2576-3.3BU TR 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 a fixed internal resistor divider to set 3.3V output - no external resistors required.
It operates in continuous conduction mode with duty cycle up to 98%, supports ON/OFF control via logic-level pin (VIH ≥2.2V, VIL ≤1.0V), and maintains regulation across –40°C to +85°C junction temperature with internal compensation eliminating need for external frequency compensation networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% over 0.5–3A load and 6–40V input - ensures stable rail for 3.3V logic without trimming. |
| Max Output Current | 3A DC - supports mid-power applications like FPGA I/O banks or microcontroller subsystems without derating. |
| Input Voltage Range | 4V to 40V - accepts wide-range unregulated inputs including automotive battery (12V nominal) and industrial 24V rails. |
| Switching Frequency | 52kHz ±10% - enables use of low-cost, high-saturation-current toroidal inductors (e.g., 330µH) with minimal EMI filtering. |
| Efficiency | 75% at 12VIN/3.3VOUT/3A - reduces thermal load vs. linear regulators, often eliminating heatsink requirement. |
| Standby Current | <200µA when ON/OFF pin = 5V - enables low-power sleep modes in battery-backed systems. |
| Protection Features | Thermal shutdown + cycle-by-cycle current limiting - prevents damage during short-circuit or overload without external circuitry. |
Pinout & Package
Package: TO-263-5 (D²PAK), surface-mount, thermally enhanced with exposed metal tab (connected to GND). Dimensions: 10.16 × 13.97 mm footprint, 4.50 mm height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Unregulated input supply | Accepts 4–40V DC; requires local 100µF input capacitor to suppress switching transients. |
| 2 - OUTPUT | Switched output node | Drives external catch diode and inductor; connects to LC filter output for regulated 3.3V. |
| 3 - GND | Power and signal ground | Common return for internal circuitry, switch emitter, and thermal pad - must be low-impedance PCB plane. |
| 4 - FEEDBACK | Regulation sense input | Internally tied to fixed 3.3V divider; left unconnected - not used in fixed-output version. |
| 5 - ON/OFF | Enable/disable control | Logic-high (≥2.2V) enables regulation; logic-low (≤1.0V) disables output and reduces quiescent current to <200µA. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output | Eliminates external feedback resistors - reduces BOM count and layout sensitivity vs. adjustable variants. |
| Integrated 3A switch | Reduces external component count to just 4: input cap, output cap, inductor, and Schottky catch diode. |
| 52kHz fixed frequency | Enables predictable EMI filtering and compatibility with low-cost, high-current inductors (e.g., AIE 415-0926). |
| Thermal shutdown | Activates at ~150°C junction temperature - protects device during sustained overload or poor heatsinking. |
| ON/OFF logic control | Supports system-level power sequencing and low-power states without external MOSFET gate drivers. |
Applications
| Industrial PLC I/O Power | Automotive Body Control Module |
|---|---|
|
Use Scenario: Powering isolated digital I/O circuits in programmable logic controllers operating from 24V DC bus. IC Role / Device Role / Timing Role: Primary 3.3V buck regulator delivering clean, regulated rail to microcontroller peripherals and optocoupler drivers. Use Value: 75% efficiency at full load minimizes heat buildup in sealed enclosures; 40V max input withstands load-dump transients. |
Use Scenario: Generating 3.3V supply for CAN transceivers and microcontrollers in vehicle body electronics. IC Role / Device Role / Timing Role: Main DC-DC converter stepping down 12V battery voltage to 3.3V logic rail with robust fault protection. Use Value: Built-in thermal shutdown and current limiting ensure reliability during cold-crank (4V) or jump-start (40V) conditions. |
| Embedded Networking Equipment | Point-of-Load for FPGA Boards |
|
Use Scenario: Providing 3.3V to Ethernet PHYs and management microcontrollers in industrial switches. IC Role / Device Role / Timing Role: Compact, high-current buck regulator replacing linear solutions to meet thermal constraints on dense PCBs. Use Value: TO-263-5 package offers superior thermal performance vs. TO-220; 3A capability supports burst-mode PHY loads. |
Use Scenario: Local 3.3V supply for FPGA configuration I/O banks and auxiliary logic on development boards. IC Role / Device Role / Timing Role: Secondary regulator deriving 3.3V from higher intermediate rail (e.g., 12V or 5V) with fast transient response. Use Value: Load transient response holds output within ±100mV during 1A–3A steps - maintains FPGA I/O integrity during configuration. |
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; TO-220-5 through-hole package with higher θJA (65°C/W vs. 45°C/W for U) | Requires heatsink at >1.5A in still air; less suitable for compact SMT-only designs | Select LM2576-3.3T only if through-hole assembly or legacy board compatibility is required. |
| MP1584EN-LF-Z | 40V input, 3A, 1.5MHz switching, adjustable output; requires external feedback resistors and has different pinout | Higher frequency allows smaller magnetics but increases EMI filtering complexity; no direct pin compatibility | Choose MP1584EN-LF-Z when board space is critical and design can accommodate 1.5MHz layout constraints. |
Compared with LM2576-3.3T, the LM2576-3.3BU TR delivers lower thermal resistance in SMT form factor; versus MP1584EN-LF-Z, it trades higher frequency for simpler design, fixed output, and proven ruggedness in industrial environments.
Availability
LM2576-3.3BU TR is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and embedded networking equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM2576-3.3BU 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 analog and mixed-signal semiconductor company acquired by Microchip Technology in 2015, known for high-reliability power management and interface ICs.
The LM2576 series was designed as a drop-in, high-efficiency replacement for three-terminal linear regulators in industrial and automotive power conversion, emphasizing simplicity, ruggedness, and minimal external component count.
FAQ
What is the maximum input voltage rating for the LM2576-3.3BU TR?
The LM2576-3.3BU TR has an absolute maximum input voltage of 45V, with recommended operating range from 4V to 40V. Exceeding 40V may trigger internal protection or reduce reliability; the device sustains 40V continuously under full load and temperature extremes per its Electrical Characteristics table.
Does the LM2576-3.3BU TR require external feedback resistors to set output voltage?
No - the LM2576-3.3BU TR is a fixed-output variant with internal resistor divider configured for 3.3V. Pin 4 (FEEDBACK) is internally connected and must remain unconnected in standard operation, unlike adjustable versions such as LM2576-ADJ.
Can the LM2576-3.3BU TR be used in automotive applications with cold-crank conditions?
Yes - the LM2576-3.3BU TR operates down to 4V input, meeting typical automotive cold-crank requirements (as low as 4.5V). Its guaranteed 3A output at 4V–40V input and thermal shutdown make it suitable for body control modules and infotainment power rails.
What is the thermal resistance (θJA) of the LM2576-3.3BU TR in standard PCB layout?
The LM2576-3.3BU TR has a junction-to-ambient thermal resistance of 45°C/W when mounted on a PCB with ~1 square inch of copper area surrounding the leads. This value assumes proper thermal pad soldering and is significantly lower than the TO-220 version's 65°C/W.
Is the LM2576-3.3BU TR RoHS compliant?
Yes - the LM2576-3.3BU TR is RoHS compliant per the manufacturer's ordering information, with exemption for "hot-melting solder" as noted in the datasheet revision M9999-082605-B. It contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits.
LM2576-3.3BU 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:
- Obsolete
- 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
LM2576-3.3BU TR FAQ
1.How can I place an order for LM2576-3.3BU TR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576-3.3BU 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 LM2576-3.3BU TR reliable?
The price and inventory of LM2576-3.3BU TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576-3.3BU TR is usually 5 days.
3.What payment methods are accepted for LM2576-3.3BU TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576-3.3BU TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576-3.3BU TR?
LM2576-3.3BU TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576-3.3BU 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 LM2576-3.3BU TR?
For technical support, including LM2576-3.3BU TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576-3.3BU TR requirements.
6.How does Aetrix verify that LM2576-3.3BU TR is sourced from the original manufacturer or authorized distributors?
All LM2576-3.3BU 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 LM2576-3.3BU TR meets industry standards.
7.What is the process for return or replacement of LM2576-3.3BU TR?
All LM2576-3.3BU TR units undergo pre-shipment inspection (PSI). If there is an issue with LM2576-3.3BU 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 LM2576-3.3BU TR part is unused and in its original packaging.
Return procedure for LM2576-3.3BU TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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