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Texas Instruments LM2576T-ADJ/LF03
- Part No.:
- LM2576T-ADJ/LF03
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2576T-ADJ/LF03.pdf
- Description:
- IC REG BUCK ADJ 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,914
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Product details
Overview
LM2576T-ADJ/LF03 from Texas Instruments is a non-synchronous step-down DC-DC converter IC delivering up to 3 A output current with adjustable output voltage (1.23 V to 37 V), fixed 52-kHz switching frequency, ±4% output voltage tolerance over line and load, and TTL-compatible ON/OFF control. It serves as the primary power conversion stage in compact industrial power supplies requiring high efficiency and minimal external components.
For engineers reviewing the LM2576T-ADJ/LF03 datasheet, LM2576T-ADJ/LF03 pinout, LM2576T-ADJ/LF03 application, or LM2576T-ADJ/LF03 equivalent, this page delivers verified technical context, validated pin functions, confirmed thermal and electrical specifications, real-world application mappings, and two rigorously cross-checked alternative parts - all grounded in TI's official SNVS107G datasheet revision March 2023.
Technical Context
The LM2576T-ADJ/LF03 integrates a 3-A NPN power switch, fixed-frequency 52-kHz oscillator, internal bandgap reference (1.23 V), error amplifier, current-limit comparator, and thermal shutdown circuit. Its architecture relies on external feedback resistors to set output voltage and requires only four external components: input capacitor, output capacitor, diode, and inductor.
It operates in continuous conduction mode under full load and transitions to discontinuous mode at light loads. Cycle-by-cycle peak current limiting (ICL = 4.2–6.9 A) and thermal shutdown provide fault protection, while the ON/OFF pin enables low-quiescent standby (50 μA typical) with TTL-level logic thresholds (VIH ≥ 2.2 V, VIL ≤ 1.2 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A DC maximum - supports medium-power loads without external current boosting. |
| Input Voltage Range | 4 V to 40 V - compatible with 5 V, 12 V, 24 V, and 36 V input rails; not rated for HV version (60 V). |
| Output Voltage Range | 1.23 V to 37 V adjustable - set via external resistor divider; feedback reference is 1.23 V ±4%. |
| Switching Frequency | 52 kHz fixed - enables use of standard off-the-shelf inductors and reduces EMI filtering complexity. |
| Efficiency | Up to 77% at VIN = 12 V, VOUT = 5 V, IOUT = 3 A - significantly higher than linear regulators, reducing thermal design burden. |
| Standby Current | 50 μA typical - enables low-power system sleep modes without auxiliary LDOs. |
| Thermal Resistance | RθJA = 32.4°C/W (KC/TO-220 package) - dictates heatsink requirement for sustained 3-A operation at elevated ambient. |
Pinout & Package
LM2576T-ADJ/LF03 uses the KC (TO-220, 5-pin) package with 10.16 mm × 8.51 mm body size and thermally enhanced metal tab connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Power input | Connects to high-side transistor collector; must be decoupled with short-path 100-μF+ electrolytic capacitor. |
| 2 - OUTPUT | Switching node | Emitter of internal NPN switch; connects directly to inductor and catch diode cathode - critical for EMI layout. |
| 3 - GROUND | Power and signal reference | Common return for input/output capacitors and feedback network; shortest possible path to CIN required. |
| 4 - FEEDBACK | Voltage sense input | Monitors output via resistor divider; 1.23 V reference sets regulation point - open for fixed versions, used for ADJ. |
| 5 - ON/OFF | Enable control | TTL-compatible shutdown: ≥2.2 V disables regulator (50 μA standby); ≤1.2 V enables switching. |
| TAB | Thermal & electrical ground | Internally tied to GND; must be soldered to large copper pour or heatsink for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 52-kHz oscillator | Enables predictable EMI spectrum and simplifies filter design - no external timing components needed. |
| Integrated 3-A NPN switch | Eliminates need for external MOSFET driver and high-side gate control logic - reduces BOM count and layout area. |
| Cycle-by-cycle current limit | Protects against short-circuit and overload by clamping peak inductor current to 4.2–6.9 A - prevents thermal runaway. |
| TTL-compatible ON/OFF | Allows direct interfacing with microcontrollers or logic sequencers without level-shifting - simplifies power sequencing. |
| ±4% output voltage tolerance | Guarantees regulation accuracy across full line/load/temperature range - avoids post-regulation trimming in production. |
Applications
| Industrial Motor Drives | Network Equipment Power |
|---|---|
|
Use Scenario: Powering gate drivers and logic circuits in 24-V brushless DC motor controllers. IC Role / Device Role / Timing Role: Primary 5-V or 12-V buck converter supplying isolated gate driver bias and MCU core voltage. Use Value: Delivers stable 3-A output with minimal external parts, enabling compact PCB layout and eliminating heat sink in many cases. |
Use Scenario: Generating 3.3-V and 5-V rails in merchant-class Ethernet switches and PoE injectors. IC Role / Device Role / Timing Role: Secondary non-isolated DC-DC stage converting 12-V intermediate bus to logic supply voltages. Use Value: Fixed-frequency operation allows predictable noise filtering; 52-kHz switching avoids audible range and eases compliance testing. |
| Test Equipment Power Supplies | Home Appliance Control Boards |
|
Use Scenario: Providing clean, adjustable bench-top power for calibration and functional test fixtures. IC Role / Device Role / Timing Role: Adjustable-output buck regulator enabling user-selectable 1.23–37 V outputs with <±4% accuracy. Use Value: Feedback pin reference (1.23 V) and wide adjustment range support flexible lab-grade output programming. |
Use Scenario: Supplying 5-V and 12-V rails to microcontroller, display, and sensor subsystems in washing machines and ovens. IC Role / Device Role / Timing Role: Main system power converter replacing linear regulators to reduce thermal stress in enclosed enclosures. Use Value: High efficiency (up to 77%) and TO-220 thermal performance enable fanless operation and extended component lifetime. |
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-5.0/LF03 | Fixed 5-V output; identical pinout, package, and thermal specs; no feedback resistor required. | Suitable where output voltage is fixed and board space is constrained - eliminates R1/R2 placement and tuning. | Select when system requires only 5 V and design simplicity outweighs adjustability needs. |
| LM2596T-ADJ | Higher 150-kHz switching frequency; lower 3-A max current; different pinout (no ON/OFF pin); requires different inductor sizing. | Better suited for space-constrained designs needing smaller magnetics; lacks TTL shutdown capability. | Choose for compact layouts where 52-kHz EMI is problematic and enable control is unnecessary. |
Compared with LM2576T-ADJ/LF03, the fixed-output LM2576T-5.0/LF03 removes design flexibility but improves reliability through reduced component count, while LM2596T-ADJ trades shutdown functionality and thermal robustness for higher frequency and smaller passive components - making each alternative optimal only within its specific constraint envelope.
Availability
LM2576T-ADJ/LF03 is available at Aetrix Electronics and suitable for industrial motor drives, network equipment power supplies, test instrumentation, home appliance control boards, and embedded power conversion requiring stable component supply and long-term manufacturability.
Supply support for LM2576T-ADJ/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 specifically for cost-sensitive, medium-power DC-DC applications where simplicity, thermal robustness, and minimal external component count are prioritized over ultra-high efficiency or advanced features like synchronization.
FAQ
What is the maximum input voltage rating for LM2576T-ADJ/LF03?
The LM2576T-ADJ/LF03 has an absolute maximum input voltage of 45 V and a recommended operating maximum of 40 V. It belongs to the standard-voltage LM2576 family - not the HV variant (LM2576HV), which supports up to 60 V. Exceeding 40 V during normal operation risks premature device failure and voids specification guarantees.
Does LM2576T-ADJ/LF03 require an external diode, and what type is recommended?
Yes, LM2576T-ADJ/LF03 requires an external Schottky catch diode connected between the OUTPUT pin and GND. The datasheet specifies a 3-A, 60-V minimum reverse voltage diode such as the 1N5822 or equivalent. Using a fast-recovery or standard PN diode increases losses and reduces efficiency due to higher forward voltage and reverse recovery time.
How is the output voltage set on LM2576T-ADJ/LF03?
The output voltage of LM2576T-ADJ/LF03 is set using a resistor divider between VOUT and GND, connected to the FEEDBACK pin. With a precise 1.23-V internal reference, VOUT = 1.23 V × (1 + R1/R2). For example, R1 = 1.21 kΩ and R2 = 1.00 kΩ yields ~2.66 V. Resistor tolerance directly impacts output accuracy - 1% metal-film resistors are recommended.
Can LM2576T-ADJ/LF03 be synchronized to an external clock?
No, LM2576T-ADJ/LF03 does not support external clock synchronization. Its 52-kHz oscillator is fully internal and fixed-frequency. Synchronization capability is absent in the LM2576 architecture - it is only available in newer families like LM76003 or LMR51430. Attempting to force sync may cause instability or damage.
What thermal considerations apply to LM2576T-ADJ/LF03 in continuous 3-A operation?
In continuous 3-A operation at full load and 40-V input, LM2576T-ADJ/LF03 dissipates significant heat. With RθJA = 32.4°C/W (TO-220), junction temperature rise can exceed safe limits without thermal relief. A minimum 25 cm² copper pour connected to the TAB and optional aluminum heatsink are required to maintain TJ < 125°C at 50°C ambient - verify with actual layout thermal simulation.
LM2576T-ADJ/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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 37V
- 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-ADJ/LF03 FAQ
1.How can I place an order for LM2576T-ADJ/LF03 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576T-ADJ/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-ADJ/LF03 reliable?
The price and inventory of LM2576T-ADJ/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-ADJ/LF03 is usually 5 days.
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4.How is shipping managed for LM2576T-ADJ/LF03?
LM2576T-ADJ/LF03 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576T-ADJ/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-ADJ/LF03?
For technical support, including LM2576T-ADJ/LF03 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576T-ADJ/LF03 requirements.
6.How does Aetrix verify that LM2576T-ADJ/LF03 is sourced from the original manufacturer or authorized distributors?
All LM2576T-ADJ/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-ADJ/LF03 meets industry standards.
7.What is the process for return or replacement of LM2576T-ADJ/LF03?
All LM2576T-ADJ/LF03 units undergo pre-shipment inspection (PSI). If there is an issue with LM2576T-ADJ/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-ADJ/LF03 part is unused and in its original packaging.
Return procedure for LM2576T-ADJ/LF03:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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