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Texas Instruments LM2576T-3.3/LF03
- Part No.:
- LM2576T-3.3/LF03
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2576T-3.3/LF03.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:175
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Product details
Overview
LM2576T-3.3/LF03 from Texas Instruments is a monolithic 3-A non-synchronous step-down DC-DC switching regulator in TO-220-5 (KC) package, delivering fixed 3.3-V output with ±4% tolerance over line and load, 52-kHz fixed-frequency operation, and TTL-compatible ON/OFF control. It replaces linear regulators in mid-power industrial and embedded power supplies where thermal efficiency and minimal external component count are critical.
For engineers reviewing the LM2576T-3.3/LF03 datasheet, LM2576T-3.3/LF03 pinout, LM2576T-3.3/LF03 application, or LM2576T-3.3/LF03 equivalent, key selection considerations include input voltage range (up to 40 V), 3-A continuous output capability, thermal performance in TO-220 package, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2576T-3.3/LF03 integrates a 3-A NPN switch, fixed 52-kHz oscillator, error amplifier, current-limit comparator, and thermal shutdown circuit. Its non-synchronous buck architecture uses an external catch diode and requires only four external components: input capacitor, output capacitor, inductor, and feedback network (shorted for fixed-output versions).
It operates in active mode when ON/OFF pin voltage is below 1.2 V (typical), entering low-power shutdown at ≤50 μA standby current when pin voltage exceeds 1.4 V. Cycle-by-cycle current limiting (ICL = 4.2–6.9 A) and thermal shutdown provide fault protection without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over full operating temperature (−40°C to +125°C) and load (0.5–3 A), enabling stable logic rail generation without trimming. |
| Max Input Voltage | 40 V - supports wide-input industrial and automotive battery-derived supplies without pre-regulation. |
| Output Current | 3 A continuous - sufficient for powering microcontrollers, FPGAs, and peripheral ICs in compact power designs. |
| Oscillator Frequency | 52 kHz (±10%) - enables use of low-cost, high-saturation-current inductors and reduces EMI filtering complexity. |
| Efficiency | 75% at VIN = 12 V, IOUT = 3 A - significantly reduces heat sink requirements versus linear regulators. |
| Standby Current | 50 μA typical - allows low-power system sleep modes without compromising fast wake-up response. |
| Saturation Voltage | 1.8 V max at IOUT = 3 A - defines minimum dropout (VIN ≥ VOUT + VSAT ≈ 5.1 V) and conduction loss budget. |
Pinout & Package
LM2576T-3.3/LF03 is housed in a TO-220-5 (KC) package with 10.16 mm × 8.51 mm body size and integral heat slug electrically connected to GROUND. The tab must be thermally coupled to a heatsink or large copper pour for reliable 3-A operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Power input | Connects to high-side transistor collector; requires short, low-inductance path to input capacitor to minimize switching noise. |
| 2 - OUTPUT | Switching node | Emitter of internal NPN switch; connects directly to inductor and cathode of external catch diode - critical for EMI layout. |
| 3 - GROUND | Power and signal reference | Common return for input/output capacitors and feedback; shortest possible trace to VIN and OUTPUT pins minimizes ground bounce. |
| 4 - FEEDBACK | Voltage sense input | Internally tied to output for fixed 3.3-V version; left unconnected or grounded per datasheet - no external divider required. |
| 5 - ON/OFF | Enable control | TTL-compatible digital input: <1.2 V = ON, >1.4 V = OFF; 50-μA standby current enables simple microcontroller or logic-level control. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output | Eliminates external resistor divider, reducing BOM count and improving long-term output stability vs. adjustable variants. |
| 52-kHz fixed-frequency oscillator | Enables predictable EMI spectrum and simplifies filter design using standard low-frequency magnetics. |
| Integrated cycle-by-cycle current limit | Protects against short-circuit and overload without external sensing, maintaining safe peak inductor current up to 6.9 A. |
| TTL-compatible ON/OFF control | Allows direct interface with 3.3-V or 5-V logic without level-shifting, supporting system-level power sequencing. |
| Thermal shutdown | Automatically disables switching above 150°C junction temperature, preventing permanent damage during sustained overload or poor heatsinking. |
Applications
| Industrial Motor Drives | Network Equipment PSU |
|---|---|
Use Scenario: Powering gate drivers and MCU cores in 24-V DC-fed brushless motor controllers. IC Role / Device Role / Timing Role: Primary 3.3-V buck regulator supplying logic and analog circuitry downstream of main DC bus. Use Value: Delivers regulated 3.3 V at up to 3 A with high efficiency, reducing thermal load on PCB and eliminating need for bulky linear regulators. | Use Scenario: Generating auxiliary 3.3-V rail in merchant-class Ethernet switch power supplies. IC Role / Device Role / Timing Role: Secondary non-isolated DC-DC stage converting 12-V intermediate bus to FPGA/ASIC core voltage. Use Value: Fixed 3.3-V output ensures compliance with logic supply tolerances while 52-kHz switching enables cost-effective magnetics selection. |
| Appliance Control Boards | Test Equipment Power Modules |
Use Scenario: Providing stable 3.3-V supply for microcontroller, display, and sensor interfaces in smart home appliances. IC Role / Device Role / Timing Role: Main system regulator converting rectified AC-derived 30–40-V DC to logic rail. Use Value: 40-V max input rating accommodates wide-line variations; TO-220 package allows direct heatsink mounting in space-constrained enclosures. | Use Scenario: Building modular, field-replaceable 3.3-V power modules for benchtop multimeters and signal generators. IC Role / Device Role / Timing Role: Standalone switching regulator module delivering precision 3.3-V output with ON/OFF control for remote enable. Use Value: TTL shutdown enables synchronized power cycling across multiple subsystems; ±4% output tolerance meets test-grade accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576T-3.3 | Same silicon, identical electrical specs; differs only in tape-and-reel packaging and RoHS compliance marking (LF03 denotes lead-free, halogen-free). | No functional difference; suitable for same PCB footprint and thermal design. | Select LM2576T-3.3/LF03 for RoHS-compliant production; LM2576T-3.3 for legacy or non-RoHS environments. |
| LM2596T-3.3 | Higher 150-kHz switching frequency, lower 3-A max output, improved efficiency (≥79%), but requires different inductor value and has different pinout (TO-220-5 with different terminal assignment). | Not pin-compatible; requires PCB redesign and new magnetics; better suited for space-constrained designs needing higher frequency. | Choose LM2596T-3.3 only if board redesign is acceptable and higher frequency/efficiency justifies requalification. |
Compared with LM2576T-3.3/LF03, the LM2576T-3.3 offers identical performance in non-RoHS form, while LM2596T-3.3 trades pin compatibility for higher frequency and marginal efficiency gains - making LM2576T-3.3/LF03 optimal for drop-in replacement and legacy design continuity.
Availability
LM2576T-3.3/LF03 is available at Aetrix Electronics and suitable for industrial motor drives, network equipment power supplies, and appliance control boards requiring stable component supply and long-lifecycle support.
Supply support for LM2576T-3.3/LF03 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2576 series was designed as a robust, easy-to-use replacement for three-terminal linear regulators in medium-power DC-DC applications - prioritizing simplicity, thermal resilience, and broad input voltage tolerance over ultra-high efficiency or miniaturization.
FAQ
What is the maximum input voltage rating for LM2576T-3.3/LF03?
The LM2576T-3.3/LF03 has a maximum input voltage rating of 40 V, as specified in the Absolute Maximum Ratings table. This allows operation from common industrial DC rails (24 V, 36 V) and rectified AC sources without additional pre-regulation. Exceeding 40 V risks permanent damage, even briefly. The HV variant (LM2576HV) supports up to 60 V but is not interchangeable with LM2576T-3.3/LF03.
Does LM2576T-3.3/LF03 require an external feedback resistor network?
No, LM2576T-3.3/LF03 does not require an external feedback resistor network. As a fixed-output version, its internal feedback divider is factory-trimmed for 3.3 V, and the FEEDBACK pin (Pin 4) is internally connected to the output. Per the datasheet, this pin should be left unconnected or tied directly to the output capacitor - no external resistors are needed or recommended.
What thermal management is required for LM2576T-3.3/LF03 at full 3-A load?
At 3-A output and typical 12-V input, LM2576T-3.3/LF03 dissipates ~2.5 W. With its TO-220-5 (KC) package RθJA of 32.4°C/W, junction temperature rise exceeds safe limits without heatsinking. A minimum 15 cm² aluminum heatsink or ≥2 oz copper thermal pad is required. The integral tab must be electrically and thermally connected to GROUND and heatsink compound applied per TI layout guidelines.
Can LM2576T-3.3/LF03 be used in synchronous buck configuration?
No, LM2576T-3.3/LF03 cannot be used in a synchronous buck configuration. It contains only a single NPN high-side switch and requires an external Schottky catch diode. Synchronous operation would require a complementary low-side MOSFET and dedicated gate drive timing - functionality absent in the LM2576 architecture. For synchronous alternatives, consider TI's LMR51430 or LM76003.
What is the purpose of the ON/OFF pin on LM2576T-3.3/LF03?
The ON/OFF pin (Pin 5) provides TTL-compatible enable/disable control for LM2576T-3.3/LF03. Pulling it low (<1.2 V) enables regulation; pulling it high (>1.4 V) places the device in low-power shutdown with 50-μA typical quiescent current. This allows precise system-level power sequencing, battery-saving sleep modes, or fault-initiated shutdown - all without modifying the main input or output paths.
LM2576T-3.3/LF03 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-5 Formed Leads
- 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
LM2576T-3.3/LF03 FAQ
1.How can I place an order for LM2576T-3.3/LF03 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576T-3.3/LF03 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 LM2576T-3.3/LF03 reliable?
The price and inventory of LM2576T-3.3/LF03 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576T-3.3/LF03 is usually 5 days.
3.What payment methods are accepted for LM2576T-3.3/LF03?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576T-3.3/LF03 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576T-3.3/LF03?
LM2576T-3.3/LF03 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576T-3.3/LF03 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 LM2576T-3.3/LF03?
For technical support, including LM2576T-3.3/LF03 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576T-3.3/LF03 requirements.
6.How does Aetrix verify that LM2576T-3.3/LF03 is sourced from the original manufacturer or authorized distributors?
All LM2576T-3.3/LF03 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 LM2576T-3.3/LF03 meets industry standards.
7.What is the process for return or replacement of LM2576T-3.3/LF03?
All LM2576T-3.3/LF03 units undergo pre-shipment inspection (PSI). If there is an issue with LM2576T-3.3/LF03, 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 LM2576T-3.3/LF03 part is unused and in its original packaging.
Return procedure for LM2576T-3.3/LF03:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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