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Texas Instruments LM2679T-12
- Part No.:
- LM2679T-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2679T-12.pdf
- Description:
- IC REG BUCK 12V 5A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:4,373
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Product details
Overview
LM2679T-12 from Texas Instruments is a monolithic 5A step-down (buck) DC/DC voltage regulator with fixed 12V output, 260 kHz internal oscillator, 120 mΩ DMOS power switch, and resistor-programmable current limit (3A–7A). It operates from 8V to 40V input and delivers ±2% output tolerance over full line/load/temperature range in industrial power conversion applications.
For engineers reviewing the LM2679T-12 datasheet, LM2679T-12 pinout, LM2679T-12 application, or LM2679T-12 equivalent, key selection considerations include its fixed 12V output, thermal shutdown protection, softstart capability, adjustable peak current limit via external resistor, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2679T-12 integrates a fixed-frequency PWM controller, high-side DMOS power switch, and internal feedback amplifier. Its 260 kHz oscillator enables predictable EMI filtering and compact passive component sizing. The device uses voltage-mode control with internal compensation, requiring no external loop compensation components for stable operation.
Current limiting is implemented via an external RADJ resistor that sets peak switch current using the formula ICL = 37,125 / RADJ (Ω), enabling design flexibility across 3A–7A fault thresholds. Thermal shutdown activates at TJ ≥ +165°C, and softstart is controlled by a linear ramp on the SS pin driven by a 3.7 µA internal current source.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±2% over −40°C to +125°C, 100 mA–5 A load, 15–40 V input |
| Input Voltage Range | 8 V to 40 V DC - supports wide industrial input rails including 24 V nominal systems |
| Switching Frequency | 260 kHz ±11% - enables use of standard low-cost inductors and predictable EMI filter design |
| Peak Switch Current Limit | Programmable 3 A to 7 A via external RADJ resistor - protects inductor/diode during overload without oversized components |
| Efficiency | Up to 92% at VIN = 24 V, IOUT = 5 A - achieved via 120 mΩ RDS(ON) DMOS switch and optimized gate drive |
| Quiescent Current | 6 mA typical at VIN = 15 V - ensures low standby power in always-on industrial subsystems |
| Thermal Shutdown | Activates at TJ ≥ +165°C - provides robust fault protection without external circuitry |
Pinout & Package
LM2679T-12 is available in TO-220 (NDZ0007B) and DDPAK (KTW0007B) packages. Both are 7-pin thermally enhanced through-hole packages with exposed drain pad for heatsinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW | Switch node | Drain of internal DMOS switch; connects to inductor and catch diode anode - carries full switching current and high dv/dt |
| VIN | Power input | Supplies bias and switch energy; requires local 3×15 µF/50 V ceramic input capacitance near pin |
| CBOOST | Bootstrap capacitor terminal | Connects 0.01 µF/50 V ceramic capacitor to VSW to generate gate overdrive voltage for low RDS(ON) |
| GND | Power and signal ground | Common return for internal circuits, switch, and feedback - must be low-inductance plane for stability |
| CURRENT ADJ | Current limit programming | Accepts RADJ resistor to ground; sets peak switch current per ICL = 37,125 / RADJ (Ω) |
| FB | Feedback input | Internal 1.21 V reference; for fixed-output versions, directly connected to output - no external divider needed |
| SOFTSTART | Softstart timing | Accepts external capacitor to ground; controls linear duty-cycle ramp-up to limit inrush current |
Key Features
| Feature | Design Value |
|---|---|
| Resistor-programmable current limit | Enables precise fault-current tailoring (3–7 A) without redesigning magnetics or diodes |
| Integrated 120 mΩ DMOS switch | Eliminates external high-side MOSFET and driver, reducing BOM count and layout complexity |
| 260 kHz fixed-frequency operation | Allows consistent EMI filter design and use of standardized inductor families from Renco, Pulse, Coilcraft |
| Softstart with external capacitor | Prevents input surge current and output overshoot during power-up without additional ICs or logic |
| ±2% output tolerance over temperature | Meets tight regulation requirements for downstream logic, analog sensors, and industrial I/O modules |
Applications
| Industrial PLC Power Supply | Battery Charger Pre-regulator |
|---|---|
Use Scenario: Provides stable 12 V rail for CPU, I/O isolation, and communication modules in programmable logic controllers operating from 24 V DC field bus. IC Role / Device Role / Timing Role: Primary step-down regulator delivering up to 5 A continuous output with thermal shutdown and current limiting for fault resilience. Use Value: Eliminates need for discrete buck controller + MOSFET + compensation network, reducing board area by >40% versus discrete solutions. | Use Scenario: Generates regulated 12 V intermediate bus from variable solar or AC/DC input for multi-stage Li-ion battery charging circuits. IC Role / Device Role / Timing Role: High-efficiency pre-regulator preceding linear or switching charge management ICs; handles wide input transients. Use Value: 92% efficiency at 24 V input/5 A load minimizes heat buildup in enclosed charger enclosures, extending thermal margin. |
| Telecom Line Card Bias | Motor Drive Auxiliary Supply |
Use Scenario: Supplies isolated 12 V bias for op-amps, ADCs, and digital isolators on telecom line cards powered from −48 V DC distribution. IC Role / Device Role / Timing Role: Non-isolated buck converter accepting 8–40 V input; used with external DC/DC isolator for secondary-side sensing. Use Value: Fixed 12 V output and ±2% tolerance ensure accurate sensor reference and DAC compliance without post-regulation. | Use Scenario: Powers gate drivers, microcontrollers, and current-sense amplifiers in 3-phase BLDC motor inverters fed from 24–40 V DC bus. IC Role / Device Role / Timing Role: Robust auxiliary supply with built-in thermal shutdown and programmable current limit to survive motor stall faults. Use Value: Resistor-adjustable 6.3 A current limit (with 5.6 kΩ) matches typical gate driver + MCU peak loads while avoiding overdesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678-12 | Same pinout, identical 12 V fixed output, but lacks adjustable current limit and softstart; 5 A rating with 150 mΩ RDS(ON) | No programmable fault threshold - less flexible for partial-load designs; no softstart increases inrush risk | Choose when cost sensitivity outweighs programmability and inrush control needs |
| TPS54560DGQ | Adjustable output (0.8–60 V), 60 V max input, 5 A, integrated compensation; requires external feedback resistors | Supports wider input range and output customization but adds design steps and component count | Choose when system requires non-standard output voltages or higher input voltage headroom |
Compared with LM2679T-12, LM2678-12 offers lower cost but sacrifices current limit adjustability and softstart, while TPS54560DGQ provides greater flexibility at the expense of fixed-voltage simplicity and increased external component count.
Availability
LM2679T-12 is available at Aetrix Electronics and suitable for industrial PLC power supplies, battery charger pre-regulators, telecom line card bias, and motor drive auxiliary supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2679T-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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies with over 90 years of innovation history.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use in industrial, automotive, and telecom power conversion where minimal external components, proven reliability, and fast time-to-market are critical.
FAQ
What is the maximum input voltage rating for the LM2679T-12?
The absolute maximum input voltage for the LM2679T-12 is 45 V DC. However, the recommended operating range is 8 V to 40 V. Operation above 40 V risks exceeding safe junction temperature limits and may trigger thermal shutdown or reduce long-term reliability. The LM2679T-12 datasheet specifies performance parameters only within the 15–40 V input range for the 12 V output version, and sustained operation beyond 40 V is not supported.
Does the LM2679T-12 require external compensation components?
No, the LM2679T-12 does not require external compensation components. It features internal frequency compensation optimized for stability with standard output capacitor ESR values and recommended inductor selections. This eliminates the need for external RC networks or type-II/type-III compensators, simplifying design and reducing bill-of-materials count. The LM2679T-12 achieves stable operation across its full load and input voltage range when used with the application-circuit guidelines in the TI datasheet SNVS026N.
How is the current limit set on the LM2679T-12?
The current limit on the LM2679T-12 is set by connecting a resistor (RADJ) between the CURRENT ADJ pin and ground. The peak switch current follows ICL = 37,125 / RADJ (Ω), yielding 6.3 A typical with a 5.6 kΩ resistor. This resistor directly programs the current threshold without additional circuitry. The LM2679T-12 monitors switch current internally and reduces switching frequency upon limit detection to limit average power dissipation during overload conditions.
Can the LM2679T-12 be used with ceramic output capacitors?
Yes, the LM2679T-12 is compatible with ceramic output capacitors, provided their total ESR is ≥13 mΩ and total capacitance meets ripple and stability requirements. TI recommends combinations such as 2 × 180 µF/16 V tantalum or aluminum electrolytic for optimal phase margin, but ceramic banks (e.g., 4 × 100 µF X7R) can be used if sufficient ESR is added via series resistors or selected with inherent ESR. Stability must be verified per Figure 10–15 in SNVS026N.
What package options are available for the LM2679T-12?
The LM2679T-12 is offered in two thermally enhanced through-hole packages: TO-220 (package number NDZ0007B) and DDPAK/TO-263 (package number KTW0007B). Both feature 7 pins and an exposed drain pad for heatsinking. The DDPAK variant provides lower thermal resistance (θJA = 26°C/W with 7.4× copper area) compared to TO-220 (θJA = 45°C/W with 4 in² copper), making it preferred for high-power-density or convection-cooled designs.
LM2679T-12 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-7 Formed Leads
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Current - Output:
- 5A
- Frequency - Switching:
- 260kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2679T-12 FAQ
1.How can I place an order for LM2679T-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679T-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 LM2679T-12 reliable?
The price and inventory of LM2679T-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2679T-12 is usually 5 days.
3.What payment methods are accepted for LM2679T-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679T-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679T-12?
LM2679T-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679T-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 LM2679T-12?
For technical support, including LM2679T-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679T-12 requirements.
6.How does Aetrix verify that LM2679T-12 is sourced from the original manufacturer or authorized distributors?
All LM2679T-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 LM2679T-12 meets industry standards.
7.What is the process for return or replacement of LM2679T-12?
All LM2679T-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2679T-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 LM2679T-12 part is unused and in its original packaging.
Return procedure for LM2679T-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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