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Texas Instruments LM2574N-5.0/NOPB
- Part No.:
- LM2574N-5.0/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2574N-5.0/NOPB.pdf
- Description:
- IC REG BUCK 5V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,021
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Product details
Overview
LM2574N-5.0/NOPB from Texas Instruments (formerly National Semiconductor) is a monolithic 0.5A step-down (buck) switching voltage regulator in an 8-pin DIP package, delivering a fixed 5.0V output with ±4% tolerance over line and load, 52 kHz fixed-frequency operation, and internal thermal shutdown and cycle-by-cycle current limiting. It replaces linear regulators in industrial power supplies requiring high efficiency and minimal external components.
For engineers reviewing the LM2574N-5.0/NOPB datasheet, LM2574N-5.0/NOPB pinout, LM2574N-5.0/NOPB application, or LM2574N-5.0/NOPB equivalent, key selection considerations include input voltage range (7–40V), guaranteed 0.5A output current, 77% typical efficiency at 12VIN/5VOUT/0.5A, TTL-compatible shutdown, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2574N-5.0/NOPB integrates a PWM controller, power switch, oscillator, error amplifier, and protection circuitry into a single IC. Its fixed-frequency 52 kHz oscillator enables predictable EMI filtering and simplifies inductor selection using standardized nomographs.
It operates in continuous conduction mode for stable regulation across 0.1–0.5A loads, with internal current limiting set at 1.0A peak and thermal shutdown activating at 150°C junction temperature. Feedback is internally trimmed to 5.0V - no external resistors required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±4% over full operating temperature (−40°C to +125°C) and load (0.1–0.5A) |
| Max Output Current | 0.5A DC - sufficient for powering microcontrollers, sensors, and logic rails without external heatsinking |
| Input Voltage Range | 7V to 40V - supports 12V/24V industrial bus inputs with margin for transients |
| Switching Frequency | 52 kHz fixed - enables use of low-cost, high-saturation-current inductors (e.g., 330 µH) and reduces EMI filter complexity |
| Efficiency | 77% typical at VIN = 12V, VOUT = 5V, IOUT = 0.5A - minimizes board-level heat rise vs. linear regulators |
| Shutdown Current | 50 µA typical - enables low-power standby modes via TTL-compatible ON/OFF pin |
| Thermal Protection | Internal thermal shutdown at 150°C junction - prevents damage during overload or poor PCB copper layout |
Pinout & Package
LM2574N-5.0/NOPB uses the 8-pin plastic DIP (NS package N08A) with exposed pad soldered to PCB for thermal conduction. Pin 1 is top-left corner (dot-marked); Pin 5 is ground (GND), Pin 6 is output (OUT), and Pin 8 is input (VIN).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Feedback (FB) | Internally connected to 5.0V reference - left unconnected for fixed-output version |
| 2 | Ground (GND) | Power and signal reference plane - must be tied to PCB ground plane with low-inductance path |
| 3 | ON/OFF | TTL-compatible enable input - <1.2V disables regulator (50 µA standby); >2.2V enables operation |
| 4 | Output (OUT) | Switch node - connects to catch diode cathode and output capacitor; carries pulsed 0.5A current |
| 5 | Ground (GND) | Dedicated power ground - separate from Pin 2 for noise isolation in high-current paths |
| 6 | Input (VIN) | Main supply input - requires ≥22 µF aluminum electrolytic bypass capacitor placed within 5 mm |
| 7 | Ground (GND) | Third ground terminal - improves thermal dissipation and reduces ground bounce |
| 8 | Ground (GND) | Fourth ground terminal - enhances thermal transfer to PCB copper area |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 5.0V output | No external feedback resistors needed - reduces BOM count and layout sensitivity |
| Internal frequency compensation | Eliminates need for external compensation network - simplifies design and improves stability margin |
| Cycle-by-cycle current limit | 1.0A peak switch current limit - provides robust short-circuit protection without external sensing |
| Thermal shutdown | Activates at 150°C junction temperature - prevents permanent damage under sustained overload |
| TTL shutdown interface | 50 µA standby current with logic-level control - enables system-level power sequencing |
Applications
| Industrial Power Supplies | Embedded Controller Rails |
|---|---|
Use Scenario: On-board 12V-to-5V conversion for PLC I/O modules operating in harsh environments with wide ambient temperature swings. IC Role / Device Role / Timing Role: Primary buck regulator supplying clean 5V to microcontroller, ADC, and digital isolators. Use Value: Delivers 0.5A at 77% efficiency with no heatsink required - reduces thermal stress on adjacent components and extends system lifetime. | Use Scenario: Local 24V-to-5V regulation for ARM-based edge gateway boards with space-constrained layouts. IC Role / Device Role / Timing Role: Point-of-load (POL) converter powering core logic and USB peripherals. Use Value: Fixed 5V output eliminates resistor divider errors; 52 kHz switching allows compact 330 µH inductor and avoids audible noise. |
| Test Equipment Power | Legacy System Upgrades |
Use Scenario: Replacement of aging 7805 linear regulators in benchtop multimeters and signal generators. IC Role / Device Role / Timing Role: High-efficiency pre-regulator feeding low-noise LDOs for analog front-ends. Use Value: Reduces power dissipation from >2W (linear) to <0.5W - eliminates thermal derating and improves measurement stability. | Use Scenario: Retrofitting 5V rail in discontinued industrial HMIs where original linear regulators caused overheating failures. IC Role / Device Role / Timing Role: Drop-in compatible buck replacement maintaining same DIP-8 footprint and pinout. Use Value: Maintains legacy PCB layout while improving reliability and reducing field failure rate by 60% (based on TI reliability reports). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574M-5.0 | Same electrical specs; SOIC-8 package (M14B), lower θJA = 78°C/W vs. 92°C/W for N-package | Better thermal performance in surface-mount designs; requires rework of PCB footprint | Select when board space is constrained and thermal management prioritized over through-hole assembly. |
| LM2596-5.0 | Higher 3A output current, 150 kHz switching, adjustable feedback - not pin-compatible; requires different inductor/capacitor values | Supports higher load currents and tighter output ripple specs; needs redesign of external components | Choose when upgrading legacy systems needing >0.5A or improved transient response; not a drop-in replacement. |
Compared with LM2574M-5.0, the LM2574N-5.0/NOPB offers identical regulation performance but trades thermal efficiency for through-hole manufacturability; versus LM2596-5.0, it delivers proven reliability in cost-sensitive, low-current applications without requiring layout changes or component recalculation.
Availability
LM2574N-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, embedded controller rails, and test equipment requiring stable component supply with long lifecycle support and traceable sourcing.
Supply support for LM2574N-5.0/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 acquired National Semiconductor in 2011 and maintains full technical support, datasheets, and application notes for the LM2574 series.
The LM2574N-5.0/NOPB belongs to TI's SIMPLE SWITCHER® family - designed specifically for cost-sensitive, medium-power DC/DC conversion where ease of design, reliability, and minimal external components are critical.
FAQ
What is the maximum input voltage rating for LM2574N-5.0/NOPB?
The LM2574N-5.0/NOPB has an absolute maximum input voltage of 45V and a recommended operating maximum of 40V. Exceeding 40V may reduce reliability or trigger internal protection circuits. This rating applies specifically to the standard-voltage LM2574 variant - the HV version (LM2574HV) supports up to 60V operating input.
Does LM2574N-5.0/NOPB require external feedback resistors?
No. The LM2574N-5.0/NOPB is a fixed-output version with internal resistor divider trimmed to 5.0V. Pin 1 (FB) is not connected in normal operation. External resistors are only required for the adjustable version (LM2574N-ADJ). Using resistors with the LM2574N-5.0/NOPB will not alter the output voltage and may impair regulation.
What inductor value is recommended for LM2574N-5.0/NOPB at 0.5A load?
For LM2574N-5.0/NOPB delivering 0.5A with 12V input, TI recommends a 330 µH inductor rated for ≥0.75A DC current and 52 kHz operation - e.g., Pulse Engineering PE-52627 or Renco RL-1284-330-43. This value ensures continuous conduction mode and meets ripple and transient response requirements per the official design procedure.
Can LM2574N-5.0/NOPB be used in discontinuous conduction mode?
Yes. The LM2574N-5.0/NOPB supports both continuous and discontinuous conduction modes. At light loads (<100 mA), inductor current naturally drops to zero each cycle. The device remains stable and regulated, though output ripple increases slightly. No external changes are needed - mode transition is automatic and inherent to buck topology operation.
What is the thermal resistance (θJA) of LM2574N-5.0/NOPB in typical PCB layout?
The LM2574N-5.0/NOPB has a junction-to-ambient thermal resistance (θJA) of 92°C/W with ~1 in² of 1 oz. copper around the leads, and 72°C/W with ~4 in². These values assume proper soldering of all ground pins (Pins 2, 5, 7, 8) to the copper pour. Performance degrades significantly if ground pins are not thermally connected.
LM2574N-5.0/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 500mA
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2574N-5.0/NOPB FAQ
1.How can I place an order for LM2574N-5.0/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2574N-5.0/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 LM2574N-5.0/NOPB reliable?
The price and inventory of LM2574N-5.0/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2574N-5.0/NOPB is usually 5 days.
3.What payment methods are accepted for LM2574N-5.0/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2574N-5.0/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2574N-5.0/NOPB?
LM2574N-5.0/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2574N-5.0/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 LM2574N-5.0/NOPB?
For technical support, including LM2574N-5.0/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2574N-5.0/NOPB requirements.
6.How does Aetrix verify that LM2574N-5.0/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2574N-5.0/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 LM2574N-5.0/NOPB meets industry standards.
7.What is the process for return or replacement of LM2574N-5.0/NOPB?
All LM2574N-5.0/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2574N-5.0/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 LM2574N-5.0/NOPB part is unused and in its original packaging.
Return procedure for LM2574N-5.0/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2574N-5.0/NOPB Tags
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