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Texas Instruments LM2574N-12/NOPB
- Part No.:
- LM2574N-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2574N-12/NOPB.pdf
- Description:
- IC REG BUCK 12V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:745
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Product details
Overview
LM2574N-12/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 12V output with ±4% tolerance over line and load, 52 kHz fixed-frequency operation, and thermal/current limiting protection. It replaces linear regulators in mid-power DC/DC conversion for industrial power supplies and embedded systems.
For engineers reviewing the LM2574N-12/NOPB datasheet, LM2574N-12/NOPB pinout, LM2574N-12/NOPB application, or LM2574N-12/NOPB equivalent, key selection considerations include input voltage range (up to 40V), guaranteed 0.5A output current, internal oscillator frequency stability (±10%), standby current (50 µA typ), and thermal shutdown behavior under sustained overload.
Technical Context
The LM2574N-12/NOPB integrates a PWM controller, power switch, oscillator, error amplifier, and protection circuitry into a single IC. Its fixed 12V output is internally trimmed and does not require external feedback resistors. The device operates in continuous conduction mode with cycle-by-cycle current limiting and thermal shutdown.
It uses a 52 kHz fixed-frequency oscillator to drive the internal NPN transistor switch, enabling predictable EMI filtering and simplified inductor selection. Input voltage rejection and load regulation are maintained across −40°C to +125°C junction temperature, with no external compensation required due to internal frequency compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12V ±4% over full line/load/temperature range - ensures stable rail for downstream logic or analog circuitry without trimming. |
| Max Output Current | 0.5A guaranteed - supports moderate-power loads such as microcontrollers, sensors, and interface ICs without external boost stages. |
| Input Voltage Range | 4V to 40V - accommodates wide-input industrial or automotive-derived supplies while maintaining regulation. |
| Oscillator Frequency | 52 kHz ±10% - enables use of low-cost, high-saturation-current off-the-shelf inductors (e.g., 330 µH) and simplifies EMI filter design. |
| Efficiency | 88% at VIN = 15V, IOUT = 0.5A - reduces thermal load on PCB copper traces, eliminating need for dedicated heatsinks in most applications. |
| Standby Current | 50 µA typical at shutdown - supports low-power sleep modes in battery-backed or energy-conscious systems. |
| Thermal Shutdown | Active at TJ ≥ 150°C - protects device during sustained overload or poor PCB heat sinking without external circuitry. |
Pinout & Package
LM2574N-12/NOPB is housed in an 8-pin plastic dual in-line package (DIP), NS package code N08A, with exposed lead frame for enhanced thermal transfer. Pin 5 (GND) must be soldered to a large copper area for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input supply connection | Accepts 4–40V unregulated DC; requires local 22 µF electrolytic bypass capacitor. |
| 2 (GND) | Power and signal reference | Common return for input/output capacitors, inductor, and catch diode; critical for noise control and thermal path. |
| 3 (OUT) | Switch node | Drives external inductor and catch diode; carries pulsed current up to 1.6A peak during switching. |
| 4 (FEEDBACK) | Output voltage sense | Internally connected to 12V reference; left unconnected for fixed-output versions. |
| 5 (GND) | Thermal pad / ground | Exposed metal tab - must be soldered to PCB copper pour for thermal dissipation and EMI reduction. |
| 6 (ON/OFF) | Shutdown control | TTL-compatible input; <1.2V disables regulator (50 µA standby), >2.2V enables normal operation. |
| 7 (GND) | Signal ground | Dedicated ground pin for internal circuitry; tied to Pin 2 and Pin 5 on PCB. |
| 8 (NC) | No internal connection | Not bonded; may be used as mechanical anchor or left floating - not electrically functional. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 12V output | Eliminates external feedback resistor network, reducing BOM count and layout sensitivity. |
| Internal frequency compensation | Enables stable operation with only four external components: input cap, output cap, inductor, and catch diode. |
| Cycle-by-cycle current limiting | Prevents destructive overcurrent events by limiting peak switch current to 1.0A typical, independent of duty cycle. |
| TTL-compatible ON/OFF control | Allows system-level power sequencing and low-power sleep states using standard logic-level signals. |
| Thermal shutdown with hysteresis | Shuts down at 150°C junction temperature and restarts after cooldown to ~135°C, preventing latch-up during transient overloads. |
Applications
| Industrial Power Supply | Embedded Controller Board |
|---|---|
Use Scenario: Converting 24V factory bus voltage to regulated 12V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary step-down regulator providing isolated, efficient, and thermally robust 12V rail. Use Value: Delivers 0.5A continuously with 88% efficiency at 15V input, minimizing board heating and eliminating need for forced-air cooling. | Use Scenario: Generating local 12V supply for FPGA configuration circuitry, level shifters, and peripheral drivers on a compact MCU carrier board. IC Role / Device Role / Timing Role: On-card buck converter replacing inefficient linear regulators to reduce thermal density. Use Value: Fixed 12V output eliminates feedback routing; 52 kHz switching allows use of small, low-cost 330 µH inductors with minimal footprint impact. |
| Automotive Aftermarket Module | Test Equipment Power Stage |
Use Scenario: Regulating variable 9–16V vehicle battery voltage to stable 12V for dashboard display controllers and CAN transceivers. IC Role / Device Role / Timing Role: Input-tolerant buck regulator with built-in transient protection and wide operating temperature range. Use Value: Withstands 40V load dump transients and operates from −40°C to +125°C junction temperature, meeting automotive environmental requirements. | Use Scenario: Providing clean, adjustable 12V bias for op-amp test fixtures and calibration references in benchtop instrumentation. IC Role / Device Role / Timing Role: Pre-regulator feeding low-noise LDOs to achieve ultra-low ripple and high PSRR. Use Value: High efficiency and low standby current (50 µA) enable precise power budgeting and extended runtime in portable test gear. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574HVN-12 | Higher input voltage rating (60V vs. 40V); identical pinout, output, and thermal specs. | Suitable for 48V industrial or telecom systems where input transients exceed 40V. | Select LM2574HVN-12 only if input voltage may reach 48–60V; otherwise LM2574N-12/NOPB offers cost and thermal advantage. |
| LM2596-12 | 3A output current, 150 kHz switching, different pinout and external component requirements. | Better suited for higher-current or space-constrained designs requiring smaller magnetics. | LM2596-12 is not pin-compatible and requires redesign; choose only when >0.5A output or higher efficiency at light loads is required. |
Compared with LM2574HVN-12, LM2574N-12/NOPB trades input voltage headroom for lower cost and optimized thermal resistance in standard DIP layout; compared with LM2596-12, it offers simpler design, proven reliability in legacy systems, and lower EMI due to 52 kHz operation - making it ideal for cost-sensitive, thermally relaxed, and noise-sensitive 0.5A applications.
Availability
LM2574N-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, embedded controller boards, automotive aftermarket modules, and test equipment power stages requiring stable component supply and long-term manufacturability.
Supply support for LM2574N-12/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 the SIMPLE SWITCHER™ product line as a portfolio of easy-to-use, highly integrated DC/DC regulators.
The LM2574N-12/NOPB belongs to the SIMPLE SWITCHER™ buck regulator family, designed specifically for engineers needing reliable, low-component-count, and thermally efficient step-down conversion in industrial, embedded, and automotive-adjacent applications.
FAQ
What is the maximum input voltage rating for LM2574N-12/NOPB?
The LM2574N-12/NOPB has an absolute maximum input voltage rating of 45V and a recommended maximum operating input voltage of 40V. Exceeding 40V risks violating the device's safe operating area, especially under high ambient temperatures or high load currents. For applications requiring >40V input, TI recommends the LM2574HVN-12 variant, which supports up to 60V input.
Does LM2574N-12/NOPB require external feedback resistors?
No, LM2574N-12/NOPB does not require external feedback resistors. As a fixed-output version, its 12V regulation is achieved via internal resistor trimming. Pin 4 (FEEDBACK) is internally connected to the 12V reference and must remain unconnected in standard operation - unlike the adjustable LM2574N-ADJ variant, which requires two external resistors.
What is the thermal resistance (θJA) of LM2574N-12/NOPB in typical PCB layout?
In a standard layout with ~1 square inch of 1 oz. copper surrounding the leads, LM2574N-12/NOPB exhibits a junction-to-ambient thermal resistance (θJA) of 92°C/W. With ~4 square inches of copper, θJA improves to 72°C/W. These values assume proper soldering of Pin 5 (exposed thermal pad) to the copper pour - failure to do so degrades thermal performance significantly.
Can LM2574N-12/NOPB be used in discontinuous conduction mode?
Yes, LM2574N-12/NOPB operates reliably in both continuous and discontinuous conduction modes. At light loads (<~50 mA), inductor current naturally drops to zero each cycle. The device maintains regulation and stability without external compensation, though output ripple increases slightly. Design guidance for discontinuous mode is provided in TI's LM2574 datasheet Figure 9 and application notes.
What type of catch diode is recommended for LM2574N-12/NOPB?
Texas Instruments recommends a Schottky diode with ≥1A average current rating and ≥20V reverse voltage rating for LM2574N-12/NOPB. Specific qualified parts include the SR102 (20V, 1A), 1N5817 (20V, 1A), or MBR120P (20V, 1A). Fast-recovery diodes like 11DQ06 (60V, 1A) are acceptable for higher input voltage margin but increase forward voltage drop and reduce efficiency.
LM2574N-12/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):
- 12V
- 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-12/NOPB FAQ
1.How can I place an order for LM2574N-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2574N-12/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-12/NOPB reliable?
The price and inventory of LM2574N-12/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-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2574N-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2574N-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2574N-12/NOPB?
LM2574N-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2574N-12/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-12/NOPB?
For technical support, including LM2574N-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2574N-12/NOPB requirements.
6.How does Aetrix verify that LM2574N-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2574N-12/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-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2574N-12/NOPB?
All LM2574N-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2574N-12/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-12/NOPB part is unused and in its original packaging.
Return procedure for LM2574N-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2574N-12/NOPB Tags
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