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Texas Instruments LM2672N-12
- Part No.:
- LM2672N-12
- Manufacturer:
- Texas Instruments
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2672N-12.pdf
- Description:
- IC REG BUCK 12V 1A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,768
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Product details
Overview
LM2672N-12 from National Semiconductor is a monolithic 1A step-down (buck) DC-DC voltage regulator in an 8-pin DIP package, featuring a fixed 12V output, 260 kHz fixed-frequency switching, 0.25 Ω DMOS power switch, and ±1.5% output voltage tolerance over line and load. It delivers high efficiency (>94% at 24VIN/1A) and integrates soft-start, frequency synchronization, TTL-compatible shutdown, thermal shutdown, and current limiting - designed for industrial power conversion where board-level heat sinking suffices.
For engineers reviewing the LM2672N-12 datasheet, LM2672N-12 pinout, LM2672N-12 application, or LM2672N-12 equivalent, key selection criteria include input voltage range (8–40V), guaranteed 1A output capability, oscillator frequency stability (±10%), standby current (50 μA), and compatibility with standard off-the-shelf inductors and Schottky catch diodes.
Technical Context
The LM2672N-12 implements a synchronous-buck topology using an integrated LDMOS power switch and internal frequency compensation (U.S. Pat. Nos. 5,382,918 and 5,514,947). Its 260 kHz oscillator enables compact LC filter design while maintaining EMI control through fixed-frequency operation and soft-start ramp control.
It operates across −40°C to +125°C junction temperature, supports external frequency synchronization up to 400 kHz, and features a dedicated ON/OFF pin with 1.4 V threshold and 20 μA typical sink current. Protection includes cycle-by-cycle current limiting (1.55 A typ), thermal shutdown, and robust input/switch voltage ratings (45 V max supply, −1 V min switch-to-ground).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V, ±1.5% tolerance over full line (15–40 VIN) and load (20 mA–1 A) range - ensures stable rail for downstream logic or analog circuitry without feedback loop tuning. |
| Switching Frequency | 260 kHz (±10%), fixed internal oscillator - enables use of standard 33–68 μH inductors and reduces filter size vs. lower-frequency buck regulators. |
| Output Current | Guaranteed 1 A continuous load current - supports mid-power applications such as FPGA core supplies or motor driver bias rails. |
| Efficiency | 94% typical at 24 VIN/1 A - minimizes power loss and eliminates need for heatsinks; PCB copper traces serve as sole thermal path. |
| Input Voltage Range | 8 V to 40 V DC - accommodates wide-input industrial, automotive (unregulated battery), and telecom power buses. |
| Quiescent Current | 2.5 mA typical (12 VIN), 50 μA standby in shutdown - enables low-power system sleep modes without auxiliary LDOs. |
| Switch RDS(ON) | 0.25 Ω typical - limits conduction loss to <125 mW at 1 A, contributing directly to high-efficiency operation. |
Pinout & Package
LM2672N-12 uses an 8-pin plastic dual in-line package (DIP) with 0.3-inch body width and through-hole mounting. Thermal resistance θJA is 95°C/W with ~1 in² copper pad - suitable for moderate-power designs without forced air.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 8–40 V DC; requires local 22 μF tantalum bypass capacitor near pin to suppress transients. |
| 2 (GND) | Power Ground | Main return path for switch current and IC bias; must connect to low-impedance ground plane under IC footprint. |
| 3 (SYNC) | Frequency Synchronization Input | Accepts external 400 kHz clock signal via RC filter (1 kΩ + 100 pF); overrides internal 260 kHz oscillator when driven. |
| 4 (SW) | Switch Node | Drives external catch diode and inductor; voltage swings from GND to VIN; layout critical for EMI and efficiency. |
| 5 (FB) | Feedback Input (N/C for fixed version) | No connection required - internally tied to 12 V output divider; unused in LM2672N-12 (fixed-output variant). |
| 6 (ON/OFF) | Shutdown Control | TTL-compatible enable: <0.8 V = shutdown (50 μA IQ), >2.0 V = active; open-circuit defaults to ON. |
| 7 (BOOST) | Bootstrap Capacitor Terminal | Connects 0.01 μF ceramic capacitor between SW and BOOST to gate-drive the internal DMOS switch fully. |
| 8 (VOUT) | Regulated Output | Delivers regulated 12 V; requires 47–68 μF output capacitor (low-ESR tantalum) placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| Patented internal frequency compensation | Eliminates need for external compensation network - simplifies design and improves transient response stability across all operating conditions. |
| Soft-start function | Controlled output ramp-up via external capacitor (CSS) - prevents inrush current and output overshoot during power-on. |
| Thermal shutdown + current limit | Protects device under overload, short-circuit, or high-temperature conditions without external circuitry - ensures robust field reliability. |
| Standard inductor compatibility | Works with off-the-shelf 33–68 μH inductors from Schott, Renco, Pulse, and Coilcraft - accelerates BOM sourcing and reduces design risk. |
| Computer-aided design support | LM267X Made Simple v6.0 software automates inductor/capacitor/diode selection and predicts efficiency, ripple, and thermal performance. |
Applications
| Industrial PLC Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Converts 24 V vehicle battery or 24 V industrial bus to clean 12 V for microcontroller, CAN transceiver, and sensor interface circuits. IC Role / Device Role / Timing Role: Primary non-isolated DC-DC buck regulator providing main 12 V system rail with high efficiency and fault protection. Use Value: Delivers 94% efficiency at 24 VIN/1 A, reducing thermal load on PCB and enabling compact enclosure design without heatsinks. |
Use Scenario: Powers 12 V logic and analog subsystems in body control units where input voltage varies from 9 V (cranking) to 16 V (charging). IC Role / Device Role / Timing Role: Fixed-output buck converter with wide 8–40 V input range and built-in soft-start to handle cold-crank transients. Use Value: ±1.5% output tolerance and 50 μA shutdown current ensure reliable MCU boot and low quiescent drain during vehicle sleep mode. |
| Test Equipment Auxiliary Rail | Legacy Industrial Instrumentation |
|
Use Scenario: Generates stable 12 V for op-amp biasing, ADC reference, and digital I/O in benchtop test instruments with unregulated AC/DC adapters. IC Role / Device Role / Timing Role: High-efficiency pre-regulator feeding linear regulators or powering noise-sensitive analog stages. Use Value: 260 kHz fixed frequency avoids audible noise and simplifies EMI filtering; 0.25 Ω RDS(ON) minimizes dropout under dynamic loads. |
Use Scenario: Replaces aging discrete buck designs in legacy programmable logic controllers and panel meters requiring long-term component availability. IC Role / Device Role / Timing Role: Monolithic drop-in replacement for multi-component switch-mode solutions - reduces bill-of-materials and assembly cost. Use Value: DIP package enables through-hole rework and field serviceability; guaranteed 1 A output supports upgraded feature sets without board redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576T-12 | 5-pin TO-220 package; 52 kHz switching; higher RDS(ON) (0.22 Ω typ but higher gate charge); no SYNC or soft-start pins. | Lower switching frequency increases inductor/capacitor size; lacks frequency synchronization and precise soft-start control. | Select LM2576T-12 only if thermal mass from TO-220 is preferred and 52 kHz operation is acceptable for EMI profile. |
| TPS54160DGQ | SOIC-10 package; 100 kHz–2.5 MHz adjustable frequency; integrated high-side FET; 0.135 Ω RDS(ON); requires external compensation. | Higher integration enables smaller solution size but demands more design effort; not pin-compatible with LM2672N-12. | Choose TPS54160DGQ for space-constrained designs needing programmable frequency and tighter output regulation (±1%), but expect added layout complexity. |
Compared with LM2576T-12, LM2672N-12 offers higher efficiency and smaller magnetics due to 260 kHz operation; versus TPS54160DGQ, it trades design flexibility for simplicity and proven DIP-mount reliability in industrial environments.
Availability
LM2672N-12 is available at Aetrix Electronics and suitable for industrial PLC power supplies, automotive body control modules, and test equipment auxiliary rails requiring stable component supply, long-lifecycle support, and through-hole manufacturability.
Supply support for LM2672N-12 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 high-performance analog and power management ICs, emphasizing ruggedness, ease-of-use, and application-ready solutions for industrial and automotive markets.
The LM2672 series was designed as a SIMPLE SWITCHER® solution to simplify high-efficiency buck regulator implementation - targeting engineers needing reliable, fixed-output DC-DC conversion with minimal external components and no compensation expertise.
FAQ
What is the minimum input voltage required for stable operation of the LM2672N-12?
The LM2672N-12 specifies a minimum operating input voltage of 8 V under all load and temperature conditions. Below this, regulation is not guaranteed - for example, at 12 V output, dropout occurs when input falls below ~13.5 V due to switch RDS(ON) and diode forward drop. Always maintain ≥8 V input with adequate margin for ripple and transients.
Can the LM2672N-12 be synchronized to an external clock, and what are the requirements?
Yes, the LM2672N-12 supports external synchronization via its SYNC pin (Pin 3). A 400 kHz square wave (≥3 VPP, 50% duty) applied through a 1 kΩ resistor and 100 pF capacitor synchronizes the internal oscillator. This allows coordinated switching in multi-rail systems to reduce beat frequencies and simplify EMI filtering.
What type of catch diode is recommended for use with the LM2672N-12?
A Schottky diode rated for ≥3.3 A average current and ≥50 V reverse voltage is recommended - e.g., IR 30WQ05F (3.3 A, 50 V). Its low forward voltage (≤0.5 V) preserves efficiency, and fast recovery avoids reverse-recovery losses. Mount it within 5 mm of the LM2672N-12 SW and GND pins to minimize parasitic inductance.
Does the LM2672N-12 require an external feedback resistor network?
No. The LM2672N-12 is a fixed-output variant - its feedback divider is internal and factory-trimmed for 12 V. Pin 5 (FB) is a no-connect terminal and must remain unconnected. External resistors are only required for the adjustable LM2672N-ADJ version.
How does thermal performance differ between the LM2672N-12 (DIP) and LM2672M-12 (SO-8)?
The LM2672N-12 has θJA = 95°C/W with 1 in² copper, while the SO-8 LM2672M-12 has θJA = 105°C/W under identical conditions. The DIP package's larger leadframe and through-hole solder joints provide slightly better heat spreading - advantageous in high-ambient or convection-cooled industrial enclosures.
LM2672N-12 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):
- 12V
- Voltage - Output (Max):
- -
- 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-12 FAQ
1.How can I place an order for LM2672N-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2672N-12 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-12 reliable?
The price and inventory of LM2672N-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2672N-12 is usually 5 days.
3.What payment methods are accepted for LM2672N-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2672N-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2672N-12?
LM2672N-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2672N-12 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-12?
For technical support, including LM2672N-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2672N-12 requirements.
6.How does Aetrix verify that LM2672N-12 is sourced from the original manufacturer or authorized distributors?
All LM2672N-12 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-12 meets industry standards.
7.What is the process for return or replacement of LM2672N-12?
All LM2672N-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2672N-12, 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-12 part is unused and in its original packaging.
Return procedure for LM2672N-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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