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Texas Instruments LM2679S-12
- Part No.:
- LM2679S-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2679S-12.pdf
- Description:
- IC REG BUCK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:2,503
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Product details
Overview
LM2679S-12 from Texas Instruments is a monolithic 5A step-down (buck) DC/DC voltage regulator with fixed 12V output, 8V–40V input range, 260 kHz fixed-frequency internal oscillator, 120 mΩ DMOS power switch, and ±2% output voltage tolerance over full line/load/temperature. It delivers high-efficiency power conversion in industrial power supplies and battery-charger pre-regulators.
For engineers reviewing the LM2679S-12 datasheet, LM2679S-12 pinout, LM2679S-12 application, or LM2679S-12 equivalent, key selection criteria include its resistor-programmable current limit (3A–7A), softstart capability via external capacitor, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2679S-12 implements a fixed-frequency PWM buck controller with internal 260 kHz oscillator and integrated 120 mΩ DMOS power switch. Its feedback loop uses a precision 1.21V reference and two-stage high-gain amplifier to maintain regulated 12V output across 100mA–5A load and 15V–40V input.
Current limiting is achieved via external RADJ resistor setting peak switch current per ICL = 37,125 / RADJ; softstart is controlled by linear charging of an external capacitor on Pin 7 to ramp duty cycle gradually; thermal shutdown activates at junction temperatures exceeding +125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12V ±2% over −40°C to +125°C, 100mA–5A load, VIN = 15V–40V |
| Input Voltage Range | 8V to 40V DC - supports wide-range industrial and battery-derived inputs |
| Switching Frequency | 260 kHz ±11% - enables use of compact magnetics and predictable EMI filtering |
| Efficiency | Up to 92% at VIN = 24V, IOUT = 5A - minimizes thermal load in high-power density designs |
| Power Switch RDS(ON) | 120 mΩ typical - reduces conduction loss and improves full-load efficiency |
| Peak Current Limit | Resistor-programmable 3A–7A via RADJ - allows inductor/diode optimization for specific fault-current requirements |
| Softstart Control | External capacitor on Pin 7 - prevents input surge current and output overshoot during power-up |
| Junction Temp Range | −40°C to +125°C - qualified for harsh industrial and automotive under-hood environments |
Pinout & Package
LM2679S-12 is available in TO-220 (NDZ0007B, 7-lead) and DDPAK (KTW0007B, 7-lead) packages. Both feature exposed thermal pads for enhanced heat dissipation and share identical pin functions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VSW (Pin 1) | Switch Node | Drives external inductor; swings between VIN and ~−0.5V during OFF-time; requires low-inductance Schottky catch diode |
| VIN (Pin 2) | Input Supply | Primary power input (8V–40V); must be bypassed with ≥3×15μF/50V ceramic or low-ESR electrolytic |
| CBOOST (Pin 3) | Bootstrap Capacitor | 0.01μF/50V ceramic connects to VSW - provides gate overdrive for low RDS(ON) operation |
| GND (Pin 4) | Power Ground | Common return for power switch, feedback, and softstart; requires low-impedance ground plane |
| CURRENT ADJ (Pin 5) | Current Limit Set | Connects to ground via RADJ resistor - sets peak switch current as ICL = 37,125 / RADJ |
| FB (Pin 6) | Feedback Input | Direct connection to 12V output - internal resistive divider fixes regulation point at 1.21V reference |
| SOFTSTART (Pin 7) | Softstart Control | Connects to ground via timing capacitor - linear ramp controls startup duty cycle to limit inrush |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 12V Output Regulation | ±2% tolerance over full temperature and load ensures stable downstream rail without external feedback components |
| Resistor-Programmable Current Limit | Adjustable 3A–7A peak switch current enables optimized inductor/diode selection and fault-current tailoring |
| Integrated 120 mΩ DMOS Power Switch | Eliminates need for external high-side MOSFET and driver, reducing BOM count and layout complexity |
| 260 kHz Fixed-Frequency Operation | Predictable switching frequency simplifies EMI filter design and enables use of standardized inductor families |
| Thermal Shutdown Protection | Automatic shutdown at TJ > +125°C prevents damage during overload or poor heatsinking conditions |
| Softstart with External Capacitor | Configurable startup time avoids input surge and output overshoot, especially critical in battery-fed systems |
Applications
| Industrial Power Supplies | Battery Charger Pre-Regulators |
|---|---|
Use Scenario: 24V industrial bus powering PLC I/O modules requiring clean, regulated 12V. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24V–36V input to stable 12V output. Use Value: Delivers 5A continuous current with 92% efficiency and ±2% output accuracy, minimizing thermal management overhead. | Use Scenario: Lead-acid or Li-ion battery charger front-end regulating variable battery voltage before linear post-regulation. IC Role / Device Role / Timing Role: High-efficiency pre-regulator stepping down 15V–40V battery pack voltage to fixed 12V intermediate rail. Use Value: Resistor-programmable current limit protects against short-circuit faults during battery connect/disconnect events. |
| Automotive Aftermarket Electronics | Telecom Line Cards |
Use Scenario: In-vehicle infotainment system powered from 12V–28V automotive battery with wide input transients. IC Role / Device Role / Timing Role: Robust buck converter supplying 12V to display backlight drivers and audio amplifiers. Use Value: −40°C to +125°C operating range and built-in thermal shutdown ensure reliability in under-dash environments. | Use Scenario: Central office line card requiring isolated 12V supply from 48V telecom bus with minimal board space. IC Role / Device Role / Timing Role: Compact, high-density DC/DC stage delivering 12V at up to 5A with low EMI profile. Use Value: 260 kHz fixed frequency enables small, standardized inductors and predictable noise filtering for compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-12 | 3A rated, 150 kHz switching frequency, no programmable current limit, higher RDS(ON) (220 mΩ) | Suitable for lower-current (<3A), cost-sensitive designs where thermal margin is less constrained | Select when 3A output suffices and softstart or precise current limiting is not required |
| LM5164QDDARQ1 | Automotive-grade, 1A rated, 500 kHz–2.2 MHz adjustable frequency, integrated high-side FET, wider 4.5V–65V input | Targeted for AEC-Q100-compliant automotive systems needing higher input voltage range and frequency flexibility | Choose for automotive applications requiring qualification, higher VIN, or programmable frequency |
Compared with LM2679S-12, LM2596S-12 offers lower cost but reduced current capability and control flexibility, while LM5164QDDARQ1 provides automotive qualification and wider input range at lower output current - making LM2679S-12 optimal for industrial 5A fixed-12V applications requiring programmable fault protection.
Availability
LM2679S-12 is available at Aetrix Electronics and suitable for industrial power supplies, battery charger pre-regulators, and automotive aftermarket electronics requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2679S-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 ICs, with decades of expertise in high-reliability power conversion solutions.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for easy-to-implement, high-efficiency step-down regulators using minimal external components for industrial and embedded power applications.
FAQ
What is the maximum input voltage rating for LM2679S-12?
The absolute maximum input voltage for LM2679S-12 is 45V DC, but the recommended operating range is 15V to 40V for 12V output operation. Exceeding 40V may degrade efficiency and thermal performance, while operation below 15V risks dropout due to minimum duty cycle limitations. The device incorporates internal protection against overvoltage stress on the VIN pin within these limits.
Does LM2679S-12 require an external feedback resistor network?
No, LM2679S-12 does not require external feedback resistors. It integrates an internal resistive divider that sets the regulated output to exactly 12V. Pin 6 (FB) connects directly to the output node, and the internal 1.21V reference ensures ±2% regulation accuracy without external components - simplifying design and improving long-term stability.
How is the current limit configured on LM2679S-12?
The current limit on LM2679S-12 is set by connecting a resistor (RADJ) between Pin 5 (CURRENT ADJ) and ground. The peak switch current follows ICL = 37,125 / RADJ, yielding 6.3A typical with 5.6 kΩ. This resistor allows precise tailoring of fault-current protection without modifying the PCB layout or adding active circuitry - a key advantage over fixed-limit alternatives.
What package options are available for LM2679S-12?
LM2679S-12 is offered in two thermally enhanced packages: TO-220 (NDZ0007B, 7-lead) and DDPAK (KTW0007B, 7-lead). Both include exposed thermal pads for direct PCB copper attachment. The DDPAK variant provides lower θJA (as low as 26°C/W with adequate copper area), while the TO-220 supports through-hole assembly and heatsink mounting.
Can LM2679S-12 operate without a softstart capacitor?
Yes, LM2679S-12 can operate without a softstart capacitor - Pin 7 (SOFTSTART) may be left open-circuited for immediate startup. However, omitting the capacitor increases input surge current and risks output voltage overshoot, especially under light-load or high-input-voltage conditions. For robustness in production systems, TI recommends a 1 nF capacitor as a default softstart configuration for LM2679S-12.
LM2679S-12 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- 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:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-7)
LM2679S-12 FAQ
1.How can I place an order for LM2679S-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679S-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 LM2679S-12 reliable?
The price and inventory of LM2679S-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2679S-12 is usually 5 days.
3.What payment methods are accepted for LM2679S-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679S-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679S-12?
LM2679S-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679S-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 LM2679S-12?
For technical support, including LM2679S-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679S-12 requirements.
6.How does Aetrix verify that LM2679S-12 is sourced from the original manufacturer or authorized distributors?
All LM2679S-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 LM2679S-12 meets industry standards.
7.What is the process for return or replacement of LM2679S-12?
All LM2679S-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2679S-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 LM2679S-12 part is unused and in its original packaging.
Return procedure for LM2679S-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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