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onsemi LM2576T-3.3
- Part No.:
- LM2576T-3.3
- Manufacturer:
- onsemi
- Package:
- TO-220-5
- Datasheet:
-
LM2576T-3.3.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,185
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Product details
Overview
LM2576T-3.3 from onsemi is a monolithic 3.0 A, 52 kHz fixed-frequency step-down (buck) switching regulator with fixed 3.3 V output, designed for high-efficiency DC-DC conversion in industrial and embedded power supplies. It operates from 7.0 V to 40 V input, delivers ±4% output voltage accuracy over line/load/temperature, and integrates thermal shutdown, cycle-by-cycle current limiting, and TTL-compatible ON/OFF control.
For engineers reviewing the LM2576T-3.3 datasheet, pinout, applications, or equivalent options, this page provides verified technical context, validated pin functions, confirmed design parameters, and two rigorously cross-referenced alternative parts for buck regulator replacement or redesign scenarios.
Technical Context
The LM2576T-3.3 implements a voltage-mode controlled buck topology with an internal 52 kHz oscillator, 1.235 V bandgap reference, and integrated 3.0 A NPN switch. Its error amplifier compares feedback voltage against the reference to adjust duty cycle via a fixed-gain comparator and driver stage.
Protection features include cycle-by-cycle current limiting (typ. 5.8 A peak at 25 °C), thermal shutdown at 150 °C junction temperature, and low-power standby mode (80 µA typical quiescent current) activated by the ON/OFF pin. The device requires only four external components: input capacitor, output capacitor, catch diode, and inductor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over −40 °C to +125 °C, 6.0–40 V input, 0.5–3.0 A load - ensures stable logic supply for microcontrollers and FPGAs without trimming. |
| Max Output Current | 3.0 A continuous - supports mid-power applications like sensor hubs or communication modules without external current boosting. |
| Input Voltage Range | 7.0 V to 40 V - accommodates wide-input industrial rails (e.g., 12 V, 24 V, 36 V battery or adapter inputs). |
| Switching Frequency | 52 kHz (±10% over full temp range) - enables use of low-cost, standard inductors and reduces EMI filtering complexity vs. MHz-range converters. |
| Efficiency | 75% typical at 12 VIN, 3.0 AOUT - significantly higher than linear regulators, minimizing heat dissipation and eliminating need for heatsink in many cases. |
| Standby Current | 80 µA typical when ON/OFF pin ≥2.4 V - enables ultra-low-power shutdown for battery-backed systems. |
| Thermal Resistance | Junction-to-case 5.0 °C/W (TO-220 package) - allows direct heatsink mounting to sustain full 3.0 A load at elevated ambient temperatures. |
Pinout & Package
LM2576T-3.3 uses the TO-220-5 (Case 314D) package with heatsink surface electrically connected to Pin 3 (GND). The exposed tab must be thermally and electrically tied to system ground for optimal thermal performance and EMI control.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Vin | Positive input supply | Accepts 7.0–40 V unregulated DC; requires local 100 µF low-ESR electrolytic bypass capacitor to suppress switching transients. |
| 2 - Output | Emiter of internal NPN switch | Drives inductor; saturation voltage ≤1.8 V at 3.0 A - dictates minimum dropout and conduction loss; PCB copper area must be minimized to reduce noise coupling. |
| 3 - GND | Circuit ground reference | Common return for input/output capacitors, feedback network, and heatsink; single-point grounding recommended to avoid ground loops. |
| 4 - Feedback | Regulated output sense input | Internally connected to 3.3 V output divider; not user-accessible in fixed versions - eliminates external resistor selection but prevents output adjustment. |
| 5 - ON/OFF | Logic-level enable/disable control | TTL-compatible: ≤1.0 V = ON, ≥2.4 V = OFF; draws ≤30 µA when active - enables microcontroller-controlled power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3 V output | Eliminates external feedback resistors, reducing BOM count and layout sensitivity while guaranteeing ±4% regulation across temperature and load. |
| Integrated 3.0 A switch | Removes need for external MOSFET and gate driver, simplifying design and improving reliability in space-constrained industrial PCBs. |
| 52 kHz fixed oscillator | Enables use of off-the-shelf, low-cost 100 µH pulse inductors (e.g., Pulse PE-92108) and avoids frequency tuning or EMI spread-spectrum complexity. |
| TTL shutdown capability | Supports low-power sleep modes with 80 µA standby current - critical for battery-powered IoT nodes requiring >1-year shelf life. |
| Full protection suite | Combines cycle-by-cycle current limit (5.8 A typ), thermal shutdown (150 °C), and safe-start circuitry - prevents damage during short-circuit or overload events. |
Applications
| Industrial PLC I/O Module | Embedded Microcontroller Power Supply |
|---|---|
|
Use Scenario: Providing clean 3.3 V rail to ARM Cortex-M4-based controller and isolated CAN/RS-485 transceivers in factory-floor automation hardware. IC Role / Device Role / Timing Role: Primary DC-DC buck regulator converting 24 V field bus to regulated 3.3 V logic supply; operates continuously at 2.2 A load with 75% efficiency. Use Value: Eliminates linear regulator heat buildup in sealed enclosures; TO-220 package mounts directly to metal chassis for passive cooling. |
Use Scenario: Powering FPGA configuration memory, ADC reference, and low-noise analog front-end in portable test equipment. IC Role / Device Role / Timing Role: Main 3.3 V supply with fast transient response (≤100 mV deviation under 1 A step load); enabled/disabled via MCU GPIO. Use Value: 80 µA standby current extends battery runtime during idle periods; fixed output avoids resistor drift-induced voltage error. |
| Automotive Body Control Unit | Point-of-Load Converter for DSP Systems |
|
Use Scenario: Generating 3.3 V for infotainment MCU and touch controller from 12 V vehicle battery with cold-crank tolerance down to 6.5 V. IC Role / Device Role / Timing Role: Input-stage buck converter preceding LDOs; handles 40 V load-dump transients via robust 45 V max input rating. Use Value: Wide 7–40 V input range maintains regulation during engine cranking and alternator surges without external TVS clamping. |
Use Scenario: Local 3.3 V supply for TI C6000 DSP core in radar signal processing board with strict ripple (<30 mVpp) requirements. IC Role / Device Role / Timing Role: High-current point-of-load regulator feeding DSP core; paired with 1000 µF output capacitor and MBR360 Schottky diode. Use Value: 52 kHz switching frequency allows effective LC filtering to meet <1% output ripple spec without ferrite beads or complex multi-stage filters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576HVT-3.3 | Extended input range (4.5–60 V) and higher junction temperature rating (150 °C); otherwise identical pinout, electrical specs, and package. | Suitable for automotive or aerospace applications requiring operation beyond 40 V input or extended thermal margin. | Select when input may exceed 40 V (e.g., 48 V telecom or 60 V industrial buses) or ambient exceeds 85 °C. |
| MP1584EN-LF-Z | Higher switching frequency (1.5 MHz), smaller solution size, but lower max output current (3 A vs. 3.0 A continuous), no integrated catch diode, and different pinout. | Better suited for compact consumer electronics where PCB area is constrained, but requires careful layout due to faster edges and external diode. | Choose for space-sensitive designs needing <1 cm² footprint; avoid if legacy TO-220 heatsink mounting or 40 V+ input is required. |
Compared with LM2576T-3.3, LM2576HVT-3.3 offers wider input voltage headroom without layout changes, while MP1584EN-LF-Z reduces board area at the cost of higher EMI filtering complexity and no drop-in compatibility.
Availability
LM2576T-3.3 is available at Aetrix Electronics and suitable for industrial PLCs, embedded microcontroller power supplies, automotive body control units, and point-of-load DSP systems requiring stable component supply and long-term manufacturability.
Supply support for LM2576T-3.3 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.
The LM2576 series was engineered as a rugged, easy-to-use buck regulator family targeting cost-sensitive industrial and embedded applications where reliability, minimal external components, and thermal resilience are critical.
FAQ
What is the maximum input voltage rating for LM2576T-3.3?
The LM2576T-3.3 has a maximum supply voltage rating of 45 V, with guaranteed operation up to 40 V input. This allows safe use in 24 V industrial systems experiencing load dump or 36 V battery applications without external clamping, as confirmed in the Absolute Maximum Ratings table of the official datasheet.
Does LM2576T-3.3 require an external feedback resistor network?
No, LM2576T-3.3 does not require external feedback resistors. As a fixed-output version, its internal resistor divider sets the regulated output to 3.3 V. Pin 4 (Feedback) is internally connected and not user-accessible - eliminating resistor selection errors and drift-related inaccuracies common in adjustable variants.
Can LM2576T-3.3 drive a 3.0 A load continuously without a heatsink?
LM2576T-3.3 can sustain 3.0 A continuously without a heatsink only under low ΔT conditions (e.g., Vin ≈ 7 V, ambient ≤40 °C). At higher input voltages (e.g., 24 V), thermal calculations show junction temperature exceeds 150 °C without heatsinking; the TO-220 package's 5.0 °C/W RθJC mandates heatsink attachment for full-load operation above 15 V input.
What diode is recommended for use with LM2576T-3.3?
The datasheet specifies the MBR360 Schottky diode (40 V, 3.0 A) as the standard catch diode for LM2576T-3.3. Its low forward voltage (≤0.55 V) minimizes conduction loss, and its fast recovery prevents reverse recovery spikes - both critical for maintaining 75% efficiency at 3.0 A output current.
Is LM2576T-3.3 RoHS-compliant and lead-free?
Yes, LM2576T-3.3 is offered in Pb-Free packages per onsemi's product marking and packaging documentation. The device meets RoHS Directive 2011/65/EU requirements, with moisture sensitivity level (MSL) rated at Level 1 - indicating unlimited floor life and no bake requirement prior to reflow soldering.
LM2576T-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 7V
- 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 FAQ
1.How can I place an order for LM2576T-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576T-3.3 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 reliable?
The price and inventory of LM2576T-3.3 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 is usually 5 days.
3.What payment methods are accepted for LM2576T-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576T-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576T-3.3?
LM2576T-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576T-3.3 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?
For technical support, including LM2576T-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576T-3.3 requirements.
6.How does Aetrix verify that LM2576T-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2576T-3.3 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 meets industry standards.
7.What is the process for return or replacement of LM2576T-3.3?
All LM2576T-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2576T-3.3, 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 part is unused and in its original packaging.
Return procedure for LM2576T-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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