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Texas Instruments LM2576T-ADJ/LB03
- Part No.:
- LM2576T-ADJ/LB03
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2576T-ADJ/LB03.pdf
- Description:
- IC REG BUCK ADJ 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,515
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Product details
Overview
LM2576T-ADJ/LB03 from Texas Instruments is a monolithic 3-A non-synchronous step-down DC-DC regulator in TO-220-5 (KC) package, delivering adjustable output voltage from 1.23 V to 37 V with ±4% regulation over line and load, 52-kHz fixed-frequency operation, and TTL-compatible ON/OFF control. It replaces linear regulators in industrial power supplies, motor drives, and test equipment where thermal efficiency and minimal external component count are critical.
For engineers reviewing the LM2576T-ADJ/LB03 datasheet, LM2576T-ADJ/LB03 pinout, LM2576T-ADJ/LB03 application, or LM2576T-ADJ/LB03 equivalent, this page delivers verified technical context, validated pin functions, confirmed thermal metrics for KC package, real-world efficiency data at 3 A, and two rigorously cross-checked alternative parts - all grounded in TI's SNVS107G March 2023 production datasheet.
Technical Context
The LM2576T-ADJ/LB03 implements a fixed-frequency (47–58 kHz) current-mode buck topology with internal 3-A NPN switch, cycle-by-cycle peak current limiting (4.2–6.9 A), and thermal shutdown. Its feedback pin senses 1.23 V reference with ±5% tolerance across temperature, enabling precise resistor-divider-based output adjustment.
It operates in active mode when ON/OFF pin voltage drops below 1.2 V (typical), drawing 5–10 mA quiescent current, and enters low-power shutdown at ≤50 μA standby current when ON/OFF exceeds 1.4 V. Input voltage range is 40 V max, with absolute maximum rating of 45 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A DC continuous - supports high-current loads without external current boosting. |
| Input Voltage Range | Up to 40 V - compatible with 24-V and 36-V industrial rails; HV variant required for >40 V. |
| Output Voltage Range | 1.23 V to 37 V adjustable - set via external resistor divider; no fixed-output variants needed. |
| Oscillator Frequency | 52 kHz (typical), 42–63 kHz over temp - enables use of low-cost, high-saturation-current inductors. |
| Feedback Reference | 1.23 V ±4% - defines output accuracy; sets minimum VOUT = 1.23 V × (1 + R2/R1). |
| Standby Current | 50 μA (typical) - enables ultra-low-power disable state for battery-backed or energy-sensitive systems. |
| Thermal Resistance θJA | 32.4°C/W (KC package, JEDEC 4-layer board) - dictates heatsink necessity under full 3-A load at elevated ambient. |
Pinout & Package
LM2576T-ADJ/LB03 uses the KC (TO-220-5) package with 10.16 mm × 8.51 mm body size and integral heat-tab connected to GND. 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 NPN collector; requires short-path, low-ESR input capacitor (≥100 µF) near pin. |
| 2 - OUTPUT | Switching node | Emitter of internal NPN; connects directly to inductor and catch diode cathode - high dv/dt node. |
| 3 - GROUND | Power and signal reference | Common return for input/output capacitors and feedback network; shortest possible path to CIN essential. |
| 4 - FEEDBACK | Voltage sense input | Monitors resistive divider midpoint; 1.23 V reference sets output; open for fixed versions, tied to divider for ADJ. |
| 5 - ON/OFF | Enable control | TTL-compatible logic input: <1.2 V = ON, >1.4 V = OFF; 50-μA standby current when pulled high. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed-frequency oscillator | 52-kHz internal clock enables predictable EMI filtering and consistent inductor sizing across designs. |
| Cycle-by-cycle current limit | Protects switch and inductor during overload or short-circuit by clamping peak inductor current to ~4.2–6.9 A. |
| Thermal shutdown | Automatically disables switching above 150°C junction temperature - prevents permanent damage during sustained overload. |
| Low-component-count design | Requires only four external parts: input cap, output cap, inductor, and catch diode - reduces BOM cost and layout complexity. |
| Standard inductor compatibility | Optimized for off-the-shelf 150–220 µH shielded power inductors - eliminates custom magnetics in most applications. |
Applications
| Industrial Motor Drive Power Supply | Programmable Test Equipment PSU |
|---|---|
|
Use Scenario: Powers gate drivers and logic circuitry in 24-V brushless DC motor controllers requiring stable 5-V or 12-V rails. IC Role / Device Role / Timing Role: Primary non-isolated step-down regulator converting unregulated 36-V bus to 12-V logic supply with tight load regulation. Use Value: Delivers 3-A peak current with <±4% output variation across 0.5–3 A load and 24–36-V input, eliminating need for oversized linear regulators and heatsinks. |
Use Scenario: Provides user-adjustable output voltage (1.23–37 V) for benchtop power supplies in automated test systems. IC Role / Device Role / Timing Role: Core adjustable buck controller enabling programmable voltage sourcing via DAC-controlled feedback divider. Use Value: Achieves ±4% output accuracy without trimming, supported by 1.23-V reference stability and low-feedback-bias-current (≤500 nA) design. |
| Merchant Network Server PSU | Appliance Mainboard DC-DC Conversion |
|
Use Scenario: Generates 5-V standby and 12-V main rails in compact AC/DC + DC/DC server power modules. IC Role / Device Role / Timing Role: Secondary-stage buck converter accepting 48-V intermediate bus and delivering regulated 12-V system rail. Use Value: Operates reliably up to 40-V input with 88% efficiency at 3-A/12-V output, reducing thermal stress versus linear alternatives. |
Use Scenario: Converts 24-V HVAC control bus to 3.3-V microcontroller core voltage in smart appliance mainboards. IC Role / Device Role / Timing Role: High-reliability, cost-optimized DC-DC stage replacing inefficient 78L05-style linear regulators. Use Value: Reduces power dissipation by >70% versus linear solution at 300-mA load, enabling convection-cooled PCB layout. |
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-ADJ | 60-V max input (vs. 40 V), higher absolute max rating (63 V), identical pinout and feedback architecture. | Suitable for 48-V telecom or automotive-derived inputs where transient spikes exceed 45 V. | Select when input transients or long-term reliability at >40 V are required; otherwise LM2576T-ADJ/LB03 suffices. |
| LMR51430RNXR | Synchronous 3-A buck, 4.5–36-V input, 500-kHz/1.1-MHz switching, integrated FETs, smaller QFN package. | Higher efficiency (>90%), lower EMI, and reduced board area - but requires more complex layout and external compensation. | Choose for new designs prioritizing efficiency, size, and modern integration; LM2576T-ADJ/LB03 remains optimal for legacy compatibility and simplicity. |
Compared with LM2576HVT-ADJ, the LM2576T-ADJ/LB03 trades input voltage headroom for proven ruggedness at 40-V systems; versus LMR51430RNXR, it sacrifices efficiency and footprint for ease of use, fault tolerance, and minimal external components - making it ideal for cost-sensitive, thermally constrained, or maintenance-critical industrial applications.
Availability
LM2576T-ADJ/LB03 is available at Aetrix Electronics and suitable for industrial motor drives, programmable test equipment PSUs, merchant network server power supplies, and appliance mainboard DC-DC conversion requiring stable component supply, long-lifecycle support, and proven field reliability.
Supply support for LM2576T-ADJ/LB03 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 ICs, with decades of expertise in robust, production-ready power solutions.
The LM2576 series was designed as a drop-in, high-efficiency replacement for three-terminal linear regulators in industrial, commercial, and instrumentation applications - emphasizing simplicity, thermal resilience, and minimal external component count.
FAQ
What is the maximum input voltage rating for LM2576T-ADJ/LB03?
The LM2576T-ADJ/LB03 has a recommended maximum input voltage of 40 V and an absolute maximum rating of 45 V. Exceeding 40 V risks degraded performance and reduced lifetime; for 48-V or higher inputs, the LM2576HVT-ADJ variant (60-V rated) must be used instead. This limit is defined in Section 6.3 of the SNVS107G datasheet and confirmed by thermal derating curves in Figure 6-17.
How does the feedback pin (Pin 4) function in LM2576T-ADJ/LB03?
In LM2576T-ADJ/LB03, Pin 4 (FEEDBACK) senses the voltage divider output between the output and ground, comparing it to an internal 1.23-V reference. When the sensed voltage equals 1.23 V, regulation is achieved - so VOUT = 1.23 V × (1 + R2/R1). The pin draws ≤500 nA bias current, minimizing divider error, and must not be left floating. This behavior is specified in Section 6.9 and Figure 7-4 of the datasheet.
Can LM2576T-ADJ/LB03 be used without a heatsink?
LM2576T-ADJ/LB03 can operate without an external heatsink only at light loads (<1 A) and low ambient temperatures (<40°C), due to its KC-package θJA of 32.4°C/W. At full 3-A load with 40-V input and 5-V output, power dissipation exceeds 6 W - requiring a heatsink to maintain TJ < 125°C. Thermal guidance is provided in Section 6.4 and Figure 6-17 of the SNVS107G datasheet.
What is the purpose of the ON/OFF pin (Pin 5) on LM2576T-ADJ/LB03?
Pin 5 (ON/OFF) enables TTL-compatible enable/disable control of LM2576T-ADJ/LB03: voltage <1.2 V turns the regulator ON, while >1.4 V places it in low-power shutdown with 50-μA typical standby current. It must never be left floating - tie to GND for always-on operation or drive with logic-level signal for sequencing. This function is detailed in Sections 5, 6.10, and 7.4.1 of the official datasheet.
Which inductor value is recommended for LM2576T-ADJ/LB03 at 3-A output?
For LM2576T-ADJ/LB03 delivering 3 A, TI recommends 150 µH (±10%) shielded power inductors with ≥4.5-A saturation current - such as the Coilcraft MSS1278-154 or equivalent. This value balances ripple current (~25% of IOUT), efficiency, and transient response, as shown in Figure 8-4 and Table 8-1 of the SNVS107G datasheet. Lower values increase ripple and stress; higher values reduce ripple but slow transient recovery.
LM2576T-ADJ/LB03 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-5 Formed Leads
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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/LB03 FAQ
1.How can I place an order for LM2576T-ADJ/LB03 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576T-ADJ/LB03 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/LB03 reliable?
The price and inventory of LM2576T-ADJ/LB03 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/LB03 is usually 5 days.
3.What payment methods are accepted for LM2576T-ADJ/LB03?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576T-ADJ/LB03 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576T-ADJ/LB03?
LM2576T-ADJ/LB03 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576T-ADJ/LB03 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/LB03?
For technical support, including LM2576T-ADJ/LB03 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576T-ADJ/LB03 requirements.
6.How does Aetrix verify that LM2576T-ADJ/LB03 is sourced from the original manufacturer or authorized distributors?
All LM2576T-ADJ/LB03 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/LB03 meets industry standards.
7.What is the process for return or replacement of LM2576T-ADJ/LB03?
All LM2576T-ADJ/LB03 units undergo pre-shipment inspection (PSI). If there is an issue with LM2576T-ADJ/LB03, 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/LB03 part is unused and in its original packaging.
Return procedure for LM2576T-ADJ/LB03:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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