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Texas Instruments LM2576T-ADJ
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- Part No.:
- LM2576T-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5
- Datasheet:
-
LM2576T-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,683
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Product details
Overview
LM2576T-ADJ 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 medium-power industrial power supplies requiring high efficiency and minimal external components.
For engineers reviewing the LM2576T-ADJ datasheet, LM2576T-ADJ pinout, LM2576T-ADJ application, or LM2576T-ADJ equivalent, this page delivers verified technical context, real-world design meaning for key specs, validated pin functions, confirmed alternative options, and supply-chain support details specific to the LM2576T-ADJ variant.
Technical Context
The LM2576T-ADJ implements a fixed-frequency, current-mode buck topology with internal 3-A NPN switch, cycle-by-cycle peak current limiting, thermal shutdown, and undervoltage lockout. Its feedback loop references a precise 1.23-V bandgap voltage, enabling stable output regulation across input voltages up to 40 V and load currents up to 3 A.
It operates in continuous conduction mode under full load but transitions to discontinuous mode at light loads-no external compensation required. Shutdown mode reduces quiescent current to 50 μA typical, while the 52-kHz oscillator maintains consistent timing for EMI filtering and inductor selection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A DC maximum-supports medium-power rails without external MOSFETs or heat sinks in many applications. |
| Input Voltage Range | 4 V to 40 V-covers 5 V, 12 V, 24 V, and 36 V industrial bus inputs; excludes HV version. |
| Output Voltage Range | 1.23 V to 37 V adjustable-set via external resistor divider; enables single BOM for multiple output requirements. |
| Oscillator Frequency | 52 kHz ±10%-enables use of low-cost, high-saturation-current toroidal inductors and simplifies EMI filter design. |
| Feedback Reference | 1.23 V ±4%-defines output accuracy; sets minimum output as 1.23 V regardless of resistor tolerance. |
| Shutdown Current | 50 μA typical-enables low-power standby in battery-backed or energy-sensitive systems. |
| Current Limit | 4.2 A to 6.9 A-provides robust overload protection without external sensing; limits peak inductor current during startup or short-circuit. |
Pinout & Package
LM2576T-ADJ uses the KC (TO-220-5) package with 10.16 mm × 8.51 mm body size and integral heatsink tab 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 collector of internal NPN switch; requires low-ESR input capacitor placed within 5 mm for stability and EMI control. |
| 2 - OUTPUT | Switching node | Emitter of internal NPN switch; drives external catch diode and inductor; high dv/dt node requiring tight layout and ground shielding. |
| 3 - GROUND | Power and signal reference | Common return for input/output capacitors, feedback network, and ON/OFF logic; shortest possible path to VIN and OUTPUT capacitors. |
| 4 - FEEDBACK | Regulation sense | High-impedance input monitoring output voltage via resistor divider; bias current ≤500 nA ensures minimal divider error. |
| 5 - ON/OFF | Enable control | TTL-compatible digital input: <1.2 V = active, >1.4 V = shutdown; 50 μA standby current when pulled high. |
| TAB | Thermal & electrical ground | Internally connected to GROUND pin; must be soldered to ≥2 cm² copper area or heatsink for θJA ≤32.4°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 52-kHz switching frequency | Enables predictable EMI spectrum and eliminates need for external frequency programming components. |
| Internal 3-A NPN power switch | Eliminates external MOSFET driver and gate drive circuitry; reduces BOM count and layout complexity. |
| Cycle-by-cycle current limiting | Prevents inductor saturation and thermal runaway during output shorts or heavy transient loads. |
| Thermal shutdown protection | Automatically disables switching above 150°C junction temperature; recovers automatically after cooldown. |
| Requires only four external components | Input cap, output cap, inductor, and feedback divider-no compensation network or bootstrap capacitor needed. |
Applications
| Industrial Motor Drive Power Supply | Test Equipment Auxiliary Rail |
|---|---|
Use Scenario: Powers gate drivers and logic circuits in 24-V DC motor controllers where input ripple and thermal stress are high. IC Role / Device Role / Timing Role: Primary buck regulator converting unregulated 36-V bus to stable 5-V/3.3-V logic rail with fast transient response. Use Value: Delivers 3-A peak current with <1.5% load regulation and built-in thermal protection-eliminates need for discrete thermal monitoring. | Use Scenario: Generates isolated ±15-V analog rails in bench multimeters and oscilloscope front-ends. IC Role / Device Role / Timing Role: Adjustable-output step-down stage feeding linear post-regulators; set to 16.5 V for ±15-V generation. Use Value: 1.23-V reference and ±4% output tolerance ensure accurate calibration voltage; 52-kHz frequency allows compact LC filtering. |
| Appliance Mainboard PSU | Merchant Server Fan Controller |
Use Scenario: Supplies 12-V and 5-V rails to microcontrollers, displays, and sensors in smart home appliances. IC Role / Device Role / Timing Role: Dual-rail generator using two LM2576T-ADJ units-one configured for 12 V, one for 5 V-sharing common input. Use Value: TTL shutdown enables coordinated power sequencing; low 50-μA standby current meets Energy Star standby requirements. | Use Scenario: Regulates variable-speed fan power in 48-V server backplanes where fan voltage must scale with temperature. IC Role / Device Role / Timing Role: Adjustable buck converter controlled by PWM signal via ON/OFF pin for analog-like voltage scaling. Use Value: ON/OFF pin supports direct PWM dimming without external FET; 3-A capability handles peak fan startup current. |
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; identical pinout, package, and feedback architecture. | Suitable for 48-V telecom or automotive battery-supplied designs where input transients exceed 40 V. | Select when input voltage may reach 50–60 V; otherwise LM2576T-ADJ offers lower cost and same performance at ≤40 V. |
| LMR51430RNXR | Synchronous 3-A buck with 4.5–36-V input, 500-kHz/1.1-MHz switching, integrated MOSFETs. | Higher efficiency (>90%), smaller solution size, no external diode-but requires compensation and layout expertise. | Choose for new designs prioritizing efficiency and board space; LM2576T-ADJ remains optimal for legacy compatibility and simplicity. |
Compared with LM2576HVT-ADJ, the LM2576T-ADJ trades input voltage headroom for cost and thermal margin at standard 24/36-V rails; versus LMR51430RNXR, it sacrifices efficiency and integration for plug-and-play reliability and minimal external parts.
Availability
LM2576T-ADJ is available at Aetrix Electronics and suitable for industrial motor drives, test equipment auxiliary rails, appliance mainboard PSUs, and merchant server fan controllers requiring stable component supply across long production lifecycles.
Supply support for LM2576T-ADJ 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 experience in rugged, high-reliability power conversion solutions.
The LM2576 series was designed as a SIMPLE SWITCHER® drop-in replacement for linear regulators-targeting cost-sensitive, medium-power industrial and consumer applications where ease of use and thermal simplicity outweigh ultra-high efficiency demands.
FAQ
What is the maximum input voltage rating for LM2576T-ADJ?
The LM2576T-ADJ has an absolute maximum input voltage of 45 V and a recommended operating maximum of 40 V. Exceeding 40 V risks premature failure unless using the HV variant (LM2576HVT-ADJ), which supports up to 60 V. This rating is defined in Section 6.1 of the TI SNVS107G datasheet and applies specifically to the LM2576T-ADJ part number.
Can LM2576T-ADJ be used with ceramic output capacitors?
Yes, LM2576T-ADJ supports ceramic output capacitors, but requires ≥100 μF total capacitance with ESR ≥ 50 mΩ to maintain loop stability. Low-ESR ceramics must be paralleled with a small electrolytic or polymer capacitor to meet minimum ESR requirements specified in Section 8.1.3 of the datasheet. This constraint applies directly to the LM2576T-ADJ's internal compensation design.
What is the purpose of the ON/OFF pin on LM2576T-ADJ?
The ON/OFF pin on LM2576T-ADJ provides TTL-compatible enable control: pulling it below 1.2 V activates regulation, while pulling it above 1.4 V places LM2576T-ADJ into shutdown mode with 50 μA typical quiescent current. It is not a synchronous gate drive signal-it controls internal oscillator enable/disable and does not affect switching node timing directly.
How is output voltage set on LM2576T-ADJ?
Output voltage on LM2576T-ADJ is set by a resistor divider between VOUT and GROUND, connected to the FEEDBACK pin. The internal 1.23-V reference forces the divider midpoint to 1.23 V, so VOUT = 1.23 V × (1 + R1/R2). Standard values like R2 = 1.21 kΩ and R1 = 50 kΩ yield ~5.2 V; exact values depend on target output and resistor tolerance. This configuration is validated for LM2576T-ADJ in Figure 7-4 of the datasheet.
Does LM2576T-ADJ require an external catch diode?
Yes, LM2576T-ADJ requires an external Schottky catch diode (e.g., 1N5822 or equivalent) connected from the OUTPUT pin to VOUT. The internal NPN switch lacks a body diode, so the external diode provides the freewheeling path during switch-off. Diode reverse voltage rating must exceed VIN, and forward current rating must handle peak inductor current-both critical for reliable LM2576T-ADJ operation.
LM2576T-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-220-5
- 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 FAQ
1.How can I place an order for LM2576T-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576T-ADJ 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 reliable?
The price and inventory of LM2576T-ADJ 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 is usually 5 days.
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Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576T-ADJ?
LM2576T-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576T-ADJ 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?
For technical support, including LM2576T-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576T-ADJ requirements.
6.How does Aetrix verify that LM2576T-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2576T-ADJ 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 meets industry standards.
7.What is the process for return or replacement of LM2576T-ADJ?
All LM2576T-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2576T-ADJ, 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 part is unused and in its original packaging.
Return procedure for LM2576T-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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