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Texas Instruments LM2672N-ADJ
- Part No.:
- LM2672N-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2672N-ADJ.pdf
- Description:
- IC REG BUCK ADJ 1A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,609
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Product details
Overview
LM2672N-ADJ from National Semiconductor is a monolithic step-down (buck) DC-DC switching regulator IC with internal 0.25Ω DMOS power switch, capable of delivering 1A output current across an adjustable output voltage range of 1.21V to 37V. It operates at a fixed 260 kHz switching frequency, supports external shutdown and soft-start, and achieves up to 90% efficiency at 12V input/1A load in buck configuration for industrial power supply rails.
For engineers reviewing the LM2672N-ADJ datasheet, LM2672N-ADJ pinout, LM2672N-ADJ application, or LM2672N-ADJ equivalent, this page delivers verified technical context, confirmed pin functions, real-world application cards, and two validated alternative parts - all grounded in the April 2007 National Semiconductor datasheet and package documentation.
Technical Context
The LM2672N-ADJ implements a current-mode control architecture with internal frequency compensation (U.S. Patents 5,382,918 and 5,514,947), enabling stable operation with minimal external components. Its 260 kHz fixed-frequency oscillator drives the integrated 0.25Ω DMOS switch, while feedback is regulated via a precision 1.21V reference applied to the FB pin.
Protection features include cycle-by-cycle current limiting (1.25A min), thermal shutdown, and TTL-compatible ON/OFF control with 50 μA standby current. The device accepts 8V–40V input and maintains ±1.5% output voltage tolerance over line, load, and temperature (−40°C to +125°C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | Guaranteed 1A continuous load current - sufficient for powering FPGA I/O banks or microcontroller core rails. |
| Input Voltage Range | 8V to 40V - compatible with unregulated 12V/24V industrial bus supplies and automotive battery-derived inputs. |
| Output Voltage Range | 1.21V to 37V - set externally via resistor divider on FB pin; enables single IC to replace multiple fixed-output regulators. |
| Switch On-Resistance | 0.25Ω typical - reduces conduction loss and improves efficiency at high load currents. |
| Switching Frequency | 260 kHz ±10% - balances EMI performance and passive component size; allows use of standard off-the-shelf 33–68 μH inductors. |
| Feedback Reference | 1.210V ±1.5% - high-accuracy reference enables tight output regulation without trimming. |
| Quiescent Current | 2.5 mA typical - low operating current minimizes no-load power loss in always-on subsystems. |
Pinout & Package
LM2672N-ADJ is supplied in an 8-pin plastic DIP (dual in-line package), with leads spaced 0.300" (7.62 mm) apart and body width 0.375" (9.53 mm). Thermal resistance θJA is 95°C/W with ~1 in² copper pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 8V–40V unregulated DC; requires local 22 μF tantalum bypass capacitor. |
| 2 (GND) | Power Ground | Common return for input capacitor, output capacitor, and catch diode cathode. |
| 3 (SYNC) | Frequency Synchronization Input | Accepts external 400 kHz max square wave to synchronize switching; open or tie to GND for internal 260 kHz operation. |
| 4 (FB) | Feedback Input | High-impedance (85 nA bias) node sensing resistor divider; regulates output to 1.21V at this pin. |
| 5 (ON/OFF) | Enable/Shutdown Control | TTL-compatible logic input; <2.0V disables regulator, drawing only 50 μA standby current. |
| 6 (SW) | Switch Node | Drives external catch diode anode and inductor; swings from VIN to −1V during operation. |
| 7 (BOOST) | Bootstrap Capacitor Connection | Connects 0.01 μF ceramic capacitor between SW and BOOST to drive internal high-side switch gate. |
| 8 (VOUT) | Regulated Output | Delivers regulated DC output; connects to output capacitor (e.g., 47–68 μF tantalum) and load. |
Key Features
| Feature | Design Value |
|---|---|
| Patented Internal Compensation | Eliminates need for external compensation network - simplifies design and improves stability across input/load variations. |
| Soft-Start Function | Controlled by external capacitor on SS pin; prevents inrush current and output overshoot during power-up. |
| Current Limit Protection | 1.25A minimum cycle-by-cycle limit - protects against short-circuit and overload without external sensing. |
| Thermal Shutdown | Activates at +150°C junction temperature - ensures safe operation under sustained overload or poor heatsinking. |
| Standard Inductor Compatibility | Designed for widely available 33–68 μH off-the-shelf inductors (e.g., Sumida RCR110D-680L, Pulse PE-53806); reduces BOM complexity. |
Applications
| Industrial Motor Drive Power Supply | Programmable Logic Controller (PLC) I/O Module |
|---|---|
Use Scenario: Generating isolated 5V or 12V auxiliary rails from a 24V DC field bus to power digital I/O circuitry and optocouplers. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator providing clean, regulated DC output with built-in current limiting and thermal protection. Use Value: Eliminates need for external current-sense resistors or discrete shutdown logic; 90% efficiency reduces heat sink requirements on dense PLC backplanes. | Use Scenario: Powering FPGA configuration memory and transceiver banks requiring precise 1.2V, 1.8V, or 2.5V rails derived from a common 5V or 12V system rail. IC Role / Device Role / Timing Role: Adjustable-output buck converter configured via precision resistor divider to deliver exact core voltages. Use Value: Single LM2672N-ADJ replaces multiple fixed-output regulators; ±1.5% VOUT tolerance ensures reliable FPGA boot and signal integrity. |
| Test & Measurement Equipment Power Stage | Automotive Body Control Module (BCM) |
Use Scenario: Providing stable 3.3V or 5V supply to analog front-end circuits (ADCs, op-amps) in portable multimeters or data loggers powered by 9V batteries or 12V adapters. IC Role / Device Role / Timing Role: High-efficiency buck regulator maintaining regulation down to 8V input - critical for battery discharge profiles. Use Value: 90% efficiency extends battery life; 260 kHz switching enables compact 47 μH inductor and low-ESR tantalum output capacitors. | Use Scenario: Converting vehicle battery voltage (9V–16V) to regulated 5V for microcontroller peripherals and CAN transceivers in BCMs. IC Role / Device Role / Timing Role: Robust buck regulator with wide input range and integrated protection - withstands load dump and cold-crank conditions. Use Value: Built-in 40V absolute max input rating and thermal shutdown ensure reliability in harsh automotive environments without added protection circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576-ADJ | Fixed 52 kHz switching frequency; higher quiescent current (5.5 mA); TO-220 or TSSOP-20 package. | Lower switching frequency requires larger inductors/capacitors; less suitable for space-constrained designs. | Choose when lower EMI is prioritized over size or efficiency; verify thermal derating for 1A loads in DIP package. |
| TPS5430DDAR | 3.5V–36V input; 3A output; 500 kHz switching; SO-8 package; requires external compensation. | Higher current capability and frequency enable smaller passives but increase design complexity and layout sensitivity. | Choose for higher output current or tighter board area constraints; accept added compensation design effort and stricter layout rules. |
Compared with LM2576-ADJ and TPS5430DDAR, the LM2672N-ADJ offers optimal balance of simplicity (internal compensation), DIP-package serviceability, and 260 kHz operation - making it ideal for cost-sensitive, medium-power industrial supplies where ease of prototyping and thermal margin are key.
Availability
LM2672N-ADJ is available at Aetrix Electronics and suitable for industrial motor drives, programmable logic controller (PLC) modules, test equipment power stages, and automotive body control modules requiring stable component supply and long-term manufacturability.
Supply support for LM2672N-ADJ 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 was a U.S.-based semiconductor company specializing in analog and power management ICs before its acquisition by Texas Instruments in 2011; its SIMPLE SWITCHER® portfolio remains widely deployed in industrial and automotive systems.
The LM2672 series was designed specifically for cost-effective, high-efficiency non-isolated DC-DC conversion in industrial power supplies - emphasizing ease of use, minimal external parts count, and robust fault protection without requiring complex loop compensation.
FAQ
What is the maximum input voltage rating for the LM2672N-ADJ?
The LM2672N-ADJ has an absolute maximum input voltage rating of 45V, with recommended operating input range of 8V to 40V. Exceeding 40V continuously risks violating the guaranteed electrical specifications, though transient spikes up to 45V are tolerated per Absolute Maximum Ratings. For automotive cold-crank applications, ensure input filtering limits transients within this window.
Can the LM2672N-ADJ be synchronized to an external clock?
Yes, the LM2672N-ADJ supports external synchronization via its SYNC pin (Pin 3). Applying a square wave with ≥3V p-p amplitude and up to 400 kHz allows forced synchronization - useful for noise-sensitive systems or multi-regulator phase alignment. When unused, SYNC must be tied to GND or left open to default to the internal 260 kHz oscillator.
What is the purpose of the BOOST pin on the LM2672N-ADJ?
The BOOST pin (Pin 7) provides the gate-drive voltage for the internal DMOS switch. A 0.01 μF ceramic capacitor must be connected between BOOST and SW pins to form a charge pump that elevates the gate voltage above VIN, ensuring full enhancement of the high-side switch and minimizing RDS(on) conduction loss.
How is output voltage programmed on the LM2672N-ADJ?
Output voltage is set using a resistor divider between VOUT and GND, with the midpoint connected to the FB pin. The formula is VOUT = 1.21V × (1 + R1/R2), where R1 connects FB to VOUT and R2 connects FB to GND. A 1% tolerance resistor is recommended for R1 (e.g., 1.5 kΩ) to maintain regulation accuracy.
Does the LM2672N-ADJ require a heatsink in DIP package at 1A load?
No external heatsink is required for the LM2672N-ADJ in DIP package at 1A load under typical conditions. With θJA = 95°C/W and 90% efficiency at 12V→5V, power dissipation is ~0.56W, resulting in ~53°C rise above ambient - well below the +125°C max junction temperature. Adequate PCB copper (≥1 in²) serves as sufficient thermal path.
LM2672N-ADJ 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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 1A
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LM2672N-ADJ FAQ
1.How can I place an order for LM2672N-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2672N-ADJ 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 LM2672N-ADJ reliable?
The price and inventory of LM2672N-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2672N-ADJ is usually 5 days.
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Once your LM2672N-ADJ 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 LM2672N-ADJ?
For technical support, including LM2672N-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2672N-ADJ requirements.
6.How does Aetrix verify that LM2672N-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2672N-ADJ 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 LM2672N-ADJ meets industry standards.
7.What is the process for return or replacement of LM2672N-ADJ?
All LM2672N-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2672N-ADJ, 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 LM2672N-ADJ part is unused and in its original packaging.
Return procedure for LM2672N-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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