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Texas Instruments LM2576T-12/LF03
- Part No.:
- LM2576T-12/LF03
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2576T-12/LF03.pdf
- Description:
- IC REG BUCK 12V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:138
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Product details
Overview
LM2576T-12/LF03 from Texas Instruments is a monolithic 3-A non-synchronous step-down (buck) DC-DC switching regulator in TO-220-5 package, delivering fixed 12-V output with ±4% regulation over line and load, 47–58-kHz internal oscillator, and 40-V max input voltage. It replaces linear regulators in high-current industrial power supplies where thermal efficiency and minimal external component count are critical.
For engineers reviewing the LM2576T-12/LF03 datasheet, LM2576T-12/LF03 pinout, LM2576T-12/LF03 application, or LM2576T-12/LF03 equivalent, key selection factors include its 3-A continuous output capability, TTL-compatible ON/OFF control with 50-μA standby current, cycle-by-cycle current limiting, thermal shutdown protection, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2576T-12/LF03 integrates a 3-A NPN power switch, fixed-frequency 52-kHz oscillator, error amplifier, bandgap reference, and thermal/current protection circuitry. Its feedback pin is internally connected to the 12-V output divider, eliminating external resistor networks for fixed-voltage operation.
It operates in continuous conduction mode under full load and transitions to discontinuous mode at light loads, maintaining regulation without requiring output capacitor ESR compensation. The device uses cycle-by-cycle peak current limiting and thermal shutdown to protect against overload and junction overheating up to 150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±4% over full operating temperature (−40°C to +125°C) and load (0.5 A to 3 A) |
| Max Input Voltage | 40 V - defines maximum unregulated DC input rail before internal transistor breakdown |
| Output Current | 3 A continuous - supports high-current loads without external current boosting |
| Oscillator Frequency | 47–58 kHz - enables use of low-cost, high-saturation-current inductors and reduces EMI filtering complexity |
| Standby Current | 50 μA typical - allows low-power shutdown mode via TTL-level ON/OFF pin control |
| Saturation Voltage | 1.4–2.0 V at 3 A - determines conduction loss and minimum dropout voltage (VIN(min) ≈ VOUT + VSAT) |
| Current Limit | 4.2–6.9 A - provides cycle-by-cycle overcurrent protection without external sensing |
Pinout & Package
LM2576T-12/LF03 is housed in a KC (TO-220-5) package with 10.16 mm × 8.51 mm body size and integral heat-transfer tab electrically connected to GND. The tab must be mounted to a heatsink or large copper pour for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Input supply connection | Connects to unregulated DC input and high-frequency bypass capacitor; shortest possible trace to minimize switching noise coupling |
| 2 - OUTPUT | Switching node | Drives external inductor and catch diode anode; high dv/dt node requiring tight layout and ground shielding |
| 3 - GROUND | Power and signal reference | Common return for input/output capacitors and feedback path; must tie directly to VIN and OUTPUT capacitor grounds |
| 4 - FEEDBACK | Regulation sense input | Internally tied to 12-V divider midpoint; left unconnected for fixed-output version - no external resistors required |
| 5 - ON/OFF | Enable/disable control | TTL-compatible logic input: ≤1.2 V = active, ≥2.2 V = shutdown; 50-μA standby current when pulled high |
| TAB | Thermal and electrical ground | Electrically connected to GND pin; requires mechanical mounting to heatsink or thermal copper plane for RθJA = 32.4°C/W |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 12-V output | Eliminates external feedback resistors, reducing BOM count and layout sensitivity while ensuring ±4% accuracy across temperature and load |
| Integrated 3-A power switch | Removes need for external MOSFET and gate driver, simplifying design and improving reliability in 12-V industrial rails |
| TTL shutdown with 50-μA standby | Enables system-level power sequencing and low-quiescent sleep modes without auxiliary LDOs or level shifters |
| Cycle-by-cycle current limit | Prevents inductor saturation and switch failure during short-circuit or startup surge without external current-sense components |
| Thermal shutdown protection | Automatically disables switching at 150°C junction temperature, preventing permanent damage during sustained overload or poor heatsinking |
Applications
| Industrial Motor Drive Power Supply | Network Equipment PSU |
|---|---|
Use Scenario: Providing regulated 12-V bias for gate drivers, logic, and sensors in 24-V/48-V DC-fed motor controllers. IC Role / Device Role / Timing Role: Primary buck converter delivering stable 12-V rail from higher bus voltage with fast transient response to PWM-driven load steps. Use Value: Delivers 3-A continuous current with <120-mV output ripple (typ.) and maintains regulation during 2-A load steps within 50 μs, minimizing gate drive droop. | Use Scenario: Generating 12-V auxiliary power for fan controllers, PHY interfaces, and management ASICs in 1U server PSUs. IC Role / Device Role / Timing Role: Secondary-stage DC-DC regulator converting 48-V backplane to isolated 12-V, synchronized via ON/OFF pin to system power-up sequence. Use Value: Enables zero-crossing soft-start via RC-delayed ON/OFF control, eliminating inrush current spikes on shared 48-V distribution bus. |
| Appliance Control Board | Test Equipment Power Module |
Use Scenario: Replacing linear regulators on white-goods main control boards to reduce heat sink size and improve energy efficiency. IC Role / Device Role / Timing Role: Fixed-output step-down regulator powering microcontroller, display backlight, and relay drivers from 24-V or 36-V battery or adapter input. Use Value: Achieves >88% efficiency at 3-A load, cutting thermal dissipation by >70% versus equivalent linear solution and enabling compact PCB layout. | Use Scenario: Building portable bench power modules with adjustable output range extended to 12 V using LM2576T-12/LF03 as base reference stage. IC Role / Device Role / Timing Role: Stable 12-V source feeding precision DACs, op-amps, and ADC references in calibrated test fixtures. Use Value: Provides ±4% output tolerance and <0.1% line regulation, meeting Class II accuracy requirements for calibration-grade instrumentation supplies. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576HVT-12 | 60-V max input (vs. 40 V), same pinout and 12-V output spec | Required for 48-V automotive or industrial systems with high transient surges | Select when input can exceed 40 V; otherwise LM2576T-12/LF03 offers lower cost and identical performance at ≤40 V |
| LMR51430RNXR | Synchronous 3-A buck, 4.5–36-V input, 500-kHz/1.1-MHz switching, integrated FETs | Higher efficiency (>92%), smaller solution size, but requires external compensation and layout optimization | Choose for new designs needing higher efficiency or smaller footprint; LM2576T-12/LF03 remains optimal for legacy drop-in replacement or cost-sensitive 40-V systems |
Compared with LM2576HVT-12, the LM2576T-12/LF03 trades input voltage headroom for lower cost and thermal simplicity; compared with LMR51430RNXR, it sacrifices efficiency and integration for ease of use, fewer external parts, and proven reliability in long-lifecycle industrial deployments.
Availability
LM2576T-12/LF03 is available at Aetrix Electronics and suitable for industrial motor drives, network equipment PSUs, appliance control boards, and test instrumentation requiring stable component supply with long-term lifecycle support.
Supply support for LM2576T-12/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 designing analog and embedded processing chips for industrial, automotive, and communications markets, with over 90 years of power management innovation.
The LM2576 series was developed as part of TI's SIMPLE SWITCHER® portfolio to provide robust, easy-to-use buck regulators that replace linear solutions in cost- and space-constrained 3-A power applications.
FAQ
What is the maximum input voltage rating for LM2576T-12/LF03?
The absolute maximum input voltage for LM2576T-12/LF03 is 45 V, but the recommended operating maximum is 40 V per TI's datasheet. Exceeding 40 V risks premature failure due to internal transistor breakdown. For 48-V systems, TI specifies the LM2576HVT-12 variant with 60-V rating. Always maintain ≥2-V margin between nominal input and 40-V limit to accommodate transients.
Does LM2576T-12/LF03 require external feedback resistors?
No, LM2576T-12/LF03 does not require external feedback resistors. As a fixed 12-V output variant, its internal resistor divider connects the FEEDBACK pin to the regulated output, eliminating external components. The FEEDBACK pin (Pin 4) must remain unconnected in standard operation - adding external resistors would disrupt regulation and is not supported.
How is thermal management implemented for LM2576T-12/LF03 in TO-220 package?
LM2576T-12/LF03 uses its metal tab (electrically connected to GND) as the primary thermal path. To achieve the specified RθJA of 32.4°C/W, the tab must be mechanically and thermally bonded to a heatsink or ≥1 in² copper pour on the PCB. Without heatsinking, power dissipation is limited to ~1.5 W at 25°C ambient; derating is required above 70°C ambient per the thermal curves in Section 6.4.
Can LM2576T-12/LF03 be synchronized to an external clock?
No, LM2576T-12/LF03 cannot be synchronized to an external clock. It uses an internal fixed-frequency oscillator (47–58 kHz) with no synchronization pin or frequency adjustment capability. For designs requiring clock synchronization or EMI reduction via spread-spectrum, TI recommends alternatives like the LMR51430 or LM76003, which support external sync and programmable frequency.
What protection features are built into LM2576T-12/LF03?
LM2576T-12/LF03 integrates cycle-by-cycle current limiting (4.2–6.9 A), thermal shutdown (150°C), and undervoltage lockout (internal). It also features TTL-compatible ON/OFF shutdown with 50-μA standby current. These protections operate autonomously without external components - no current-sense resistors, thermal sensors, or enable logic are needed to achieve full fault coverage.
LM2576T-12/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):
- 12V
- 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-12/LF03 FAQ
1.How can I place an order for LM2576T-12/LF03 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576T-12/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-12/LF03 reliable?
The price and inventory of LM2576T-12/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-12/LF03 is usually 5 days.
3.What payment methods are accepted for LM2576T-12/LF03?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576T-12/LF03 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576T-12/LF03?
LM2576T-12/LF03 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576T-12/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-12/LF03?
For technical support, including LM2576T-12/LF03 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576T-12/LF03 requirements.
6.How does Aetrix verify that LM2576T-12/LF03 is sourced from the original manufacturer or authorized distributors?
All LM2576T-12/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-12/LF03 meets industry standards.
7.What is the process for return or replacement of LM2576T-12/LF03?
All LM2576T-12/LF03 units undergo pre-shipment inspection (PSI). If there is an issue with LM2576T-12/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-12/LF03 part is unused and in its original packaging.
Return procedure for LM2576T-12/LF03:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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