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Texas Instruments LM2576S-3.3/NOPB
- Part No.:
- LM2576S-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2576S-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:332
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Product details
Overview
LM2576S-3.3/NOPB from Texas Instruments is a monolithic 3-A non-synchronous step-down DC-DC converter with fixed 3.3-V output, 40-V maximum input voltage, 52-kHz fixed-frequency oscillator, ±4% output voltage tolerance over line and load, and TTL-compatible ON/OFF control. It replaces linear regulators in industrial power supplies requiring high efficiency and minimal external components.
For engineers reviewing the LM2576S-3.3/NOPB datasheet, LM2576S-3.3/NOPB pinout, LM2576S-3.3/NOPB application, or LM2576S-3.3/NOPB equivalent, key selection criteria include input voltage range (up to 40 V), thermal performance in TO-220 package, cycle-by-cycle current limiting, standby current of 50 µA, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2576S-3.3/NOPB integrates a 3-A NPN switch, fixed-frequency 52-kHz oscillator, error amplifier with 1.23-V internal reference, thermal shutdown, and cycle-by-cycle current limiting. Its feedback pin is internally connected to the 3.3-V output, eliminating external resistor dividers.
It operates in continuous conduction mode under full load and transitions to discontinuous mode at light loads. Shutdown is asserted when ON/OFF pin voltage exceeds 1.4 V, reducing quiescent current to 50 µA typical - enabling low-power standby in motor drives and test equipment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over full operating temperature (−40°C to +125°C) and load (0.5 A to 3 A), ensuring stable logic rail generation without trimming. |
| Max Input Voltage | 40 V - supports 24-V and 36-V industrial bus inputs with margin for transients. |
| Output Current | 3 A DC - delivers sufficient power for FPGA I/O banks, microcontroller cores, or sensor signal chains without external parallel stages. |
| Oscillator Frequency | 52 kHz ±10% - enables use of low-cost, high-saturation-current toroidal inductors and reduces EMI filtering complexity vs. MHz-range converters. |
| Efficiency | 75% at 12-V input / 3-A load - cuts heat sink size by >50% versus equivalent linear regulators, often eliminating heatsink entirely. |
| Standby Current | 50 µA typical - allows battery-backed systems to maintain >1-year shelf life during storage or deep sleep modes. |
| Saturation Voltage | 1.8 V max at 3 A - defines minimum dropout: VIN(MIN) = 3.3 V + 1.8 V = 5.1 V, enabling operation from single-cell LiFePO4 or dual-cell alkaline sources. |
Pinout & Package
LM2576S-3.3/NOPB uses the KC (TO-220, 5-pin) package with integrated heat slug tied to GROUND. The tab must be thermally connected to a PCB copper pour or external heatsink for reliable 3-A operation at ambient temperatures up to +70°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Power input | Connects to collector of internal NPN switch; requires short, low-inductance path to ≥100-µF input capacitor to suppress switching noise. |
| 2 - OUTPUT | Switching node | Emitter of internal NPN switch; connects directly to inductor and catch diode anode - critical high-dI/dt node requiring tight loop layout. |
| 3 - GROUND | Power and signal reference | Common return for input/output capacitors, feedback network, and ON/OFF control; must tie to VIN and OUTPUT capacitor grounds with minimal trace length. |
| 4 - FEEDBACK | Regulation sense | Internally connected to 3.3-V output; no external divider needed - simplifies layout and eliminates resistor tolerance errors. |
| 5 - ON/OFF | Enable control | TTL-compatible digital input: <1.2 V = active, >1.4 V = shutdown; 50-µA standby current enables direct MCU GPIO control without level shifting. |
| TAB | Thermal pad | Internally connected to GROUND; must be soldered to ≥1.6 in² copper area or heatsink to achieve RθJA = 32.4°C/W and sustain full 3-A load. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output | Eliminates external feedback resistors, reducing BOM count, layout area, and calibration drift - ideal for space-constrained embedded controllers. |
| Cycle-by-cycle current limit | Protects internal switch and external diode/inductor during short-circuit or overload; limits peak inductor current to 5.8 A typical, preventing saturation and thermal runaway. |
| Thermal shutdown | Activates at 150°C junction temperature and latches off until cooldown - prevents permanent damage during sustained overload or poor heatsinking. |
| 52-kHz fixed-frequency operation | Enables predictable EMI filtering design and compatibility with low-cost, high-current inductors optimized for ≤100-kHz switching - avoids ferrite core losses seen in MHz converters. |
| TTL shutdown interface | Supports direct connection to 3.3-V or 5-V logic outputs without pull-up resistors or level translators - simplifies system-level power sequencing in multi-rail supplies. |
Applications
| Industrial Motor Drives | Network Equipment PSU |
|---|---|
Use Scenario: Powering gate drivers, position sensors, and MCU peripherals in 24-V brushless DC motor controllers. IC Role / Device Role / Timing Role: Primary 3.3-V buck regulator supplying logic rails and analog front-end circuitry. Use Value: Delivers 3 A continuously with <4% output variation across 15–40-V input swings and −40°C to +85°C ambient - maintaining real-time control loop integrity. | Use Scenario: Generating 3.3-V bias for Ethernet PHYs, packet processors, and fan controllers in merchant-switch PSUs. IC Role / Device Role / Timing Role: Secondary regulated rail derived from 12-V intermediate bus. Use Value: Achieves 75% efficiency at full load while meeting EN55022 Class B conducted EMI limits due to deterministic 52-kHz switching frequency. |
| Appliance Control Boards | Test & Measurement Front Ends |
Use Scenario: Supplying microcontroller, display driver, and touch-sensing circuitry in smart home appliances with wide AC-DC adapter input variation. IC Role / Device Role / Timing Role: Main 3.3-V system regulator with enable control synchronized to user interface wake events. Use Value: 50-µA standby current extends battery backup runtime; ON/OFF pin allows MCU to disable supply during idle periods without software overhead. | Use Scenario: Providing clean, stable 3.3-V power to precision ADC references, op-amp signal chains, and FPGA configuration memory in portable DMMs and oscilloscopes. IC Role / Device Role / Timing Role: Low-noise post-regulator following a higher-voltage switching stage. Use Value: ±4% output tolerance and <10-mV ripple (with recommended LC filter) ensure <1-LSB error in 16-bit ADC conversions across temperature and load. |
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-3.3 | Same electrical specs but TO-220-5 package without exposed tab; RθJA = 42.6°C/W vs. 32.4°C/W for LM2576S-3.3/NOPB. | Lower thermal performance limits continuous 3-A operation to lower ambient temperatures unless oversized heatsink is used. | Select LM2576S-3.3/NOPB when full 3-A load must be sustained at >60°C ambient or board space prohibits large heatsinks. |
| LM2596S-3.3 | Higher 150-kHz switching frequency, 3-A rating, but only 40-V max input and no HV variant; requires smaller inductor but increases EMI filtering burden. | Better suited for compact consumer devices where size outweighs EMI certification effort; not drop-in compatible due to different pinout and feedback architecture. | Choose LM2596S-3.3 only if board redesign accommodates new layout and higher-frequency EMI mitigation - not for LM2576S-3.3/NOPB replacement. |
Compared with LM2576T-3.3, LM2576S-3.3/NOPB delivers superior thermal management via its exposed ground tab, enabling higher ambient operation without derating. Versus LM2596S-3.3, it trades higher-frequency EMI challenges for robust 52-kHz operation with proven industrial reliability and simpler magnetics selection.
Availability
LM2576S-3.3/NOPB is available at Aetrix Electronics and suitable for industrial motor drives, merchant network equipment PSUs, appliance control boards, and test & measurement front ends requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2576S-3.3/NOPB 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The LM2576xx series was designed as a robust, easy-to-use SIMPLE SWITCHER® solution for replacing linear regulators in cost-sensitive, thermally constrained 3-A power conversion applications - emphasizing fault protection, minimal external parts, and wide-input-voltage capability.
FAQ
What is the maximum input voltage rating for LM2576S-3.3/NOPB?
The absolute maximum input voltage for LM2576S-3.3/NOPB is 45 V, with recommended operation up to 40 V. This rating applies specifically to the standard LM2576 (non-HV) version; the HV variant (LM2576HV) supports up to 60 V. Exceeding 45 V risks permanent damage to the internal NPN switch and is not recoverable.
Does LM2576S-3.3/NOPB require external feedback resistors?
No, LM2576S-3.3/NOPB does not require external feedback resistors. Its FEEDBACK pin is internally connected to the 3.3-V output, providing a fixed regulation point. This eliminates resistor tolerance errors, reduces component count, and simplifies PCB layout - a key differentiator from adjustable versions like LM2576ADJ.
What thermal management is required to sustain 3-A output with LM2576S-3.3/NOPB?
To sustain 3-A continuous output, LM2576S-3.3/NOPB requires its exposed ground tab to be soldered to ≥1.6 in² of 2-oz copper on the PCB or attached to an external heatsink. Without this, junction temperature exceeds 150°C under full load at ambient >60°C, triggering thermal shutdown. The KC package's RθJA drops from 42.6°C/W (TO-220 non-tab) to 32.4°C/W with proper tab thermal coupling.
Can LM2576S-3.3/NOPB be used in battery-powered applications with low standby power requirements?
Yes, LM2576S-3.3/NOPB supports ultra-low-power operation via its ON/OFF pin: applying >1.4 V places the device in shutdown mode with 50 µA typical standby current. This enables multi-year battery life in remote sensors or backup systems - confirmed in Section 6.10 of the official TI datasheet SNVS107G.
How does the current-limit protection function in LM2576S-3.3/NOPB?
LM2576S-3.3/NOPB implements cycle-by-cycle peak current limiting, clamping switch current to 5.8 A typical. When overload occurs, the device maintains regulation until current hits the limit, then holds duty cycle constant - preventing inductor saturation and thermal runaway. This behavior is documented in Section 7.4.3 and Table 6.10 of the LM2576 datasheet.
LM2576S-3.3/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- 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):
- 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:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LM2576S-3.3/NOPB FAQ
1.How can I place an order for LM2576S-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576S-3.3/NOPB 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 LM2576S-3.3/NOPB reliable?
The price and inventory of LM2576S-3.3/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576S-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM2576S-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576S-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576S-3.3/NOPB?
LM2576S-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576S-3.3/NOPB 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 LM2576S-3.3/NOPB?
For technical support, including LM2576S-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576S-3.3/NOPB requirements.
6.How does Aetrix verify that LM2576S-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2576S-3.3/NOPB 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 LM2576S-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2576S-3.3/NOPB?
All LM2576S-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2576S-3.3/NOPB, 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 LM2576S-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2576S-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2576S-3.3/NOPB Tags
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