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Texas Instruments LM2671N-5.0
- Part No.:
- LM2671N-5.0
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2671N-5.0.pdf
- Description:
- IC REG BUCK 5V 500MA 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,845
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Product details
Overview
LM2671N-5.0 from National Semiconductor is a monolithic 500mA step-down (buck) DC-DC switching regulator in an 8-pin DIP package, delivering a fixed 5.0V output with ±1.5% tolerance over line and load, 260 kHz fixed-frequency operation, and 90% efficiency at 12V input/500mA load. It integrates a 0.25Ω DMOS power switch, soft-start, TTL-compatible shutdown, and thermal/current limiting - used in industrial power supplies and embedded system pre-regulation.
For engineers reviewing the LM2671N-5.0 datasheet, LM2671N-5.0 pinout, LM2671N-5.0 application, or LM2671N-5.0 equivalent, key selection criteria include input voltage range (6.5–40V), guaranteed 500mA output current, standby quiescent current (50 μA), oscillator frequency tolerance (±10%), and thermal resistance (95°C/W in N-package).
Technical Context
The LM2671N-5.0 implements a current-mode buck topology with internal 260 kHz oscillator, patented frequency compensation, and integrated 0.25Ω DMOS switch. Its control loop uses feedback from the output via an internal 1.21V reference and external resistor divider (not required for fixed 5.0V version).
It supports external synchronization (pin 3), soft-start via capacitor on pin 5, and shutdown via TTL-level signal on pin 6. Protection includes cycle-by-cycle current limiting and thermal shutdown, enabling robust operation under fault conditions without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.5% over full line/load/temperature range - ensures stable logic supply without post-regulation. |
| Max Output Current | 500mA continuous - sufficient to power microcontrollers, sensors, and interface ICs directly. |
| Input Voltage Range | 6.5V to 40V - supports wide-input industrial and automotive battery-derived rails. |
| Switching Frequency | 260 kHz ±10% - enables use of compact, low-cost inductors and capacitors while avoiding AM band interference. |
| Efficiency | 90% at VIN = 12V, IOUT = 500mA - minimizes thermal stress; PCB copper traces suffice as heatsink. |
| Quiescent Current | 2.5 mA typical operating, 50 μA standby - enables low-power sleep modes in battery-backed systems. |
| Thermal Resistance | 95°C/W (Junction-to-Ambient, N-package) - defines maximum power dissipation before thermal shutdown. |
Pinout & Package
LM2671N-5.0 is housed in an 8-pin plastic dual in-line package (DIP), through-hole mount, with standard MO8A/N08E footprint and 0.3" width. Pin 1 is marked with a notch or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Supply | DC input rail (6.5–40V); requires local 22μF tantalum bypass capacitor. |
| 2 (GND) | Power Ground | Common return for input, output, and internal circuits; must connect to low-impedance ground plane. |
| 3 (SYNC) | Frequency Sync Input | Accepts external clock (up to 400 kHz) to synchronize switching; leave open for internal 260 kHz operation. |
| 4 (SW) | Switch Node | Drives external catch diode and inductor; high dv/dt node requiring short PCB traces. |
| 5 (SS) | Soft-Start Control | Connects to capacitor to control startup ramp time; open for default start-up. |
| 6 (ON/OFF) | Shutdown Input | TTL-compatible enable: <0.8V = off (50 μA standby), >2.0V = on; pulls up internally. |
| 7 (FB) | Feedback Input | Internally connected to 5.0V output divider; not accessible on fixed-output versions. |
| 8 (BOOST) | Bootstrap Capacitor Terminal | Connects to 0.01μF ceramic capacitor between SW and BOOST to drive high-side switch gate. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 0.25Ω DMOS Switch | Reduces conduction loss and eliminates need for external MOSFET, simplifying BOM and layout. |
| Patented Internal Compensation | Eliminates external compensation components - only 5 external parts required for full operation. |
| 260 kHz Fixed-Frequency Operation | Enables predictable EMI filtering and consistent inductor sizing across designs. |
| TTL-Compatible Shutdown | Allows direct interfacing with microcontroller GPIOs without level-shifting circuitry. |
| Thermal + Current Limit Protection | Prevents damage during overload, short-circuit, or inadequate heatsinking - no external sensing needed. |
Applications
| Industrial PLC Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Converts 12–24V vehicle battery or 24V industrial bus to clean 5V for MCU and CAN transceivers. IC Role / Device Role / Timing Role: Primary buck regulator supplying core logic voltage; operates continuously with transient load steps up to 500mA. Use Value: 90% efficiency reduces heat buildup in sealed enclosures; 40V max input withstands load-dump transients. |
Use Scenario: Powers microcontroller, EEPROM, and sensor interfaces in body electronics modules. IC Role / Device Role / Timing Role: Pre-regulator feeding low-noise LDOs; enabled/disabled via vehicle ignition signal on ON/OFF pin. Use Value: 50 μA standby current extends battery life during vehicle sleep mode; DIP package supports manual rework in low-volume assembly. |
| Test Equipment Auxiliary Rail | Legacy Industrial Controller Upgrade |
|
Use Scenario: Generates isolated 5V rail for digital I/O and communication interfaces in benchtop instruments. IC Role / Device Role / Timing Role: Standalone switching regulator replacing aging linear regulators to improve thermal performance. Use Value: 260 kHz switching avoids audible noise; soft-start prevents inrush-induced voltage droop on shared input rails. |
Use Scenario: Retrofit replacement for obsolete 7805-based supplies in field-deployed controllers. IC Role / Device Role / Timing Role: Drop-in compatible buck upgrade offering higher current and efficiency than linear alternatives. Use Value: Same 8-pin DIP footprint and pinout as legacy linear regulators; supports existing PCB layouts without redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2574N-5.0 | Lower 52 kHz switching frequency; 0.5A max output; no sync or soft-start pins. | Requires larger inductor/capacitor; less suitable for space-constrained or low-EMI designs. | Choose when cost sensitivity outweighs size/efficiency needs and 52 kHz operation is acceptable. |
| TPS5430DR | 3A output, 500 kHz switching, SO-8 package; requires external compensation and more external components. | Higher current and frequency support smaller magnetics but increase design complexity and layout sensitivity. | Choose when >500mA load or tighter regulation is required; not drop-in due to different pinout and control architecture. |
Compared with LM2671N-5.0, LM2574N-5.0 offers simpler implementation at lower frequency and cost, while TPS5430DR delivers higher performance at the expense of increased external component count and layout rigor - neither is pin-compatible, but both serve overlapping mid-power buck applications.
Availability
LM2671N-5.0 is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and test equipment requiring stable component supply with long-term manufacturability and through-hole assembly compatibility.
Supply support for LM2671N-5.0 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
National Semiconductor (now part of Texas Instruments) specialized in analog and power management ICs, emphasizing ease-of-use, integration, and ruggedness for industrial and automotive applications.
The LM2671 series was designed as a SIMPLE SWITCHER® solution to simplify switch-mode power supply design - targeting engineers needing reliable, high-efficiency buck conversion with minimal external components and no compensation expertise.
FAQ
What is the maximum input voltage rating for the LM2671N-5.0?
The absolute maximum input voltage for the LM2671N-5.0 is 45V, but the recommended operating range is 6.5V to 40V per the datasheet. Exceeding 40V may compromise long-term reliability or trigger overvoltage protection in some units. The LM2671N-5.0 is commonly used with 12V, 24V, or 36V industrial rails within this safe window.
Does the LM2671N-5.0 require external compensation components?
No, the LM2671N-5.0 features patented internal frequency compensation (U.S. Patents 5,382,918 and 5,514,947), eliminating the need for external compensation networks. This allows the LM2671N-5.0 to operate stably with only five external components: input capacitor, output capacitor, catch diode, inductor, and boost capacitor.
Can the LM2671N-5.0 be synchronized to an external clock?
Yes, the LM2671N-5.0 supports external frequency synchronization via pin 3 (SYNC). Applying a square wave (≥3Vpp, ≤400 kHz) through a 1 kΩ resistor and 100 pF capacitor synchronizes the internal oscillator. This capability enables noise reduction in multi-rail systems and allows inductor downsizing - a feature not available in basic linear regulators or older buck ICs like the LM2574N-5.0.
What is the thermal performance of the LM2671N-5.0 in its DIP package?
The LM2671N-5.0 has a junction-to-ambient thermal resistance (θJA) of 95°C/W in the 8-pin DIP (N) package with ~1 in² of copper on the PCB. At 500mA output and 12V input, power dissipation is ~350mW, resulting in ~33°C temperature rise above ambient - well within the +125°C max junction limit. No heatsink is required under typical conditions.
Is the LM2671N-5.0 pin-compatible with other members of the LM2671 family?
Yes, all LM2671 variants - including LM2671N-3.3, LM2671N-12, LM2671N-ADJ, and their SO-8/LLP counterparts - share identical pinouts and package footprints. The LM2671N-5.0 can be substituted with another fixed-output variant without PCB changes, provided input/output requirements and thermal limits remain compatible.
LM2671N-5.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 500mA
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2671N-5.0 FAQ
1.How can I place an order for LM2671N-5.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2671N-5.0 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 LM2671N-5.0 reliable?
The price and inventory of LM2671N-5.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2671N-5.0 is usually 5 days.
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We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2671N-5.0 transactions.
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4.How is shipping managed for LM2671N-5.0?
LM2671N-5.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2671N-5.0 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 LM2671N-5.0?
For technical support, including LM2671N-5.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2671N-5.0 requirements.
6.How does Aetrix verify that LM2671N-5.0 is sourced from the original manufacturer or authorized distributors?
All LM2671N-5.0 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 LM2671N-5.0 meets industry standards.
7.What is the process for return or replacement of LM2671N-5.0?
All LM2671N-5.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2671N-5.0, 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 LM2671N-5.0 part is unused and in its original packaging.
Return procedure for LM2671N-5.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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