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Texas Instruments LM2679S-ADJ/NOPB
- Part No.:
- LM2679S-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2679S-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:478
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Product details
Overview
LM2679S-ADJ/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC regulator with adjustable output (1.2 V to 37 V), 260-kHz fixed-frequency PWM control, 120-mΩ DMOS high-side switch, ±2% output voltage tolerance, and resistor-programmable current limit (5.5–7.6 A at 25°C). It delivers high-efficiency power conversion in industrial power supplies and battery chargers.
For engineers reviewing the LM2679S-ADJ/NOPB datasheet, LM2679S-ADJ/NOPB pinout, LM2679S-ADJ/NOPB application, or LM2679S-ADJ/NOPB equivalent, key selection criteria include input voltage range (8–40 V), soft-start timing via external capacitor, feedback reference voltage (1.21 V), thermal shutdown protection, and TO-263-7 package compatibility with high-current PCB layouts.
Technical Context
The LM2679S-ADJ/NOPB implements a voltage-mode PWM controller with a fixed 260-kHz oscillator and internal error amplifier referenced to a 1.21-V feedback threshold. Its DMOS power switch supports continuous 5-A output with peak current limiting set by an external resistor (RADJ = 5.6 kΩ yields 6.3-A typical limit).
Functional blocks include bootstrapped high-side gate drive (CB pin), soft-start ramp generator (SS pin), and thermal shutdown circuitry activating above 150°C junction temperature. The device operates across –40°C to +125°C and requires no external compensation for stable operation with standard output capacitors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5 A continuous - supports high-power loads without external current-sharing circuitry |
| Input Voltage Range | 8 V to 40 V - enables direct use with 12-V, 24-V, and 36-V industrial or automotive supply rails |
| Output Voltage Range | 1.2 V to 37 V adjustable - configured via external resistor divider on FB pin |
| Feedback Reference | 1.21 V ±1.2% - sets output accuracy and stability across temperature and load |
| Switch RDS(ON) | 0.14 Ω max at 25°C - minimizes conduction loss and improves efficiency at full load |
| Oscillator Frequency | 260 kHz ±11% - enables use of compact off-the-shelf inductors and reduces EMI compared to higher frequencies |
| Current Limit Range | 3 A to 7 A programmable - set by RADJ (e.g., 5.6 kΩ → 6.3 A typical), protecting against short-circuit faults |
| Efficiency | 84% typical at 12-VIN/5-VOUT/5-A - achieved via low-RDS(ON) switch and optimized gate drive |
Pinout & Package
LM2679S-ADJ/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (10.10 mm × 8.89 mm), rated for high-power dissipation and compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch Output | Drain node of internal DMOS FET; connects to inductor and Schottky diode cathode - switching node requiring tight layout |
| 2 (VIN) | Input Supply | Main power input (8–40 V); must be bypassed with low-ESR capacitors placed adjacent to pin |
| 3 (CB) | Bootstrap Capacitor | Connects to SW via 0.01-μF ceramic capacitor to enable full gate drive for high-side FET |
| 4 (GND) | Power Ground | Primary ground return for input/output capacitors and thermal pad - requires low-inductance plane connection |
| 5 (IADJ) | Current Limit Adjust | Input for resistor-to-ground (e.g., 5.6 kΩ) setting peak switch current per ICL = 37,125/RADJ |
| 6 (FB) | Feedback Input | Sense input for output voltage divider; 1.21-V reference enables precise adjustable output regulation |
| 7 (SS) | Soft-Start | Capacitor-to-ground (e.g., 1 nF) controls output voltage ramp time 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 adding external sense circuits |
| Integrated 120-mΩ DMOS switch | Eliminates need for external MOSFET and driver, reducing BOM count and layout complexity |
| 260-kHz fixed-frequency operation | Allows predictable EMI filtering and use of standardized, cost-optimized inductors from multiple vendors |
| ±2% output voltage tolerance | Meets tight regulation requirements for sensitive analog or digital loads without post-regulation |
| Thermal shutdown protection | Automatically disables switching above 150°C junction temperature, preventing damage during overload or poor heatsinking |
| Soft-start with external capacitor | Prevents input surge current and output overshoot during power-up, improving system reliability |
Applications
| Industrial Power Supply | Battery Charger |
|---|---|
Use Scenario: 24-V input converted to 13.8-V/5-A for lead-acid battery float charging in telecom cabinets. IC Role / Device Role / Timing Role: Primary buck regulator providing constant-voltage/constant-current charging profile with programmable current limit. Use Value: Resistor-adjustable current limit ensures safe charge termination without external current-sense amplifiers or microcontroller intervention. |
Use Scenario: 36-V vehicle electrical system powering a 12-V auxiliary battery bank in mobile equipment. IC Role / Device Role / Timing Role: High-efficiency preregulator stepping down unregulated input before linear post-regulation. Use Value: 84% efficiency at 5-A load minimizes heat generation in confined chassis space, eliminating need for forced-air cooling. |
| Programmable Lab PSU | Embedded System Power |
Use Scenario: Bench power supply with user-selectable 1.2–37-V output using front-panel potentiometer and display. IC Role / Device Role / Timing Role: Adjustable-output DC/DC core enabling wide-range voltage programming via FB divider. Use Value: 1.21-V reference and ±2% tolerance support accurate, stable output across full adjustment range without calibration. |
Use Scenario: 15-V rail conversion to 3.3-V/3-A for FPGA and peripheral ICs in ruggedized edge computing hardware. IC Role / Device Role / Timing Role: Main system power converter operating from wide-input industrial bus with thermal robustness. Use Value: –40°C to +125°C operating range and integrated thermal shutdown ensure reliable operation in uncontrolled ambient environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678-5.0/NOPB | Fixed 5-V output; no FB pin or adjustable current limit; identical 5-A rating and 260-kHz frequency | Used where output voltage is static and current-limit tuning is unnecessary | Select when design requires only 5-V output and simplified feedback network |
| LM2596-ADJ | 3-A output rating; 150-kHz switching frequency; higher RDS(ON) (0.22 Ω); no programmable current limit | Lower-cost solution for <3-A loads with relaxed efficiency and thermal requirements | Choose for cost-sensitive, lower-current designs where 5-A capability is not required |
Compared with LM2678-5.0/NOPB, LM2679S-ADJ/NOPB provides design flexibility through output adjustability and current-limit programming; versus LM2596-ADJ, it delivers higher current, better efficiency, and enhanced protection features - making it suitable for demanding industrial and battery systems.
Availability
LM2679S-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery chargers, programmable lab PSUs, and embedded system power rails requiring stable component supply and long-term manufacturability.
Supply support for LM2679S-ADJ/NOPB 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 decades of expertise in high-reliability power conversion ICs.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family - designed specifically for easy, robust, and efficient non-isolated DC/DC buck conversion in industrial, automotive, and communications equipment.
FAQ
What is the recommended input capacitor configuration for LM2679S-ADJ/NOPB?
The LM2679S-ADJ/NOPB requires three 15-μF/50-V ceramic or low-ESR electrolytic capacitors placed as close as possible to the VIN and GND pins. This configuration handles high RMS input ripple current (2.5 A typical) and suppresses high-frequency noise from the switching node. Layout best practice mandates short, wide traces between VIN, CIN, and GND to minimize parasitic inductance that could cause instability or voltage spikes.
How does the current limit adjustment work on LM2679S-ADJ/NOPB?
The LM2679S-ADJ/NOPB uses an external resistor (RADJ) from the IADJ pin to GND to set peak switch current via ICL = 37,125 / RADJ. With RADJ = 5.6 kΩ, LM2679S-ADJ/NOPB delivers 6.3 A typical current limit. This resistor-based method eliminates external current-sense components and allows precise fault-current tailoring across 3–7 A without modifying the power stage.
Can LM2679S-ADJ/NOPB operate with an input voltage below 8 V?
No - LM2679S-ADJ/NOPB has a minimum specified input voltage of 8 V per its absolute maximum and recommended operating conditions. Operation below 8 V may result in failure to start, unstable regulation, or undefined behavior. The internal bias circuitry and DMOS gate drive require sufficient headroom to function reliably, and no characterization data exists for sub-8-V operation.
What thermal considerations apply to LM2679S-ADJ/NOPB in TO-263 package?
In the TO-263-7 (KTW) package, LM2679S-ADJ/NOPB achieves 26°C/W junction-to-ambient thermal resistance with 7.4× paddle-area copper and 12 vias to inner layers. For 5-A continuous operation, maintain PCB copper area ≥1.0064 in² under the exposed pad, use ≥6 thermal vias, and avoid enclosing the device in sealed enclosures without airflow. Thermal shutdown activates at ~150°C junction temperature.
Is LM2679S-ADJ/NOPB RoHS-compliant and lead-free?
Yes - LM2679S-ADJ/NOPB carries the /NOPB suffix, indicating lead-free (Pb-free) packaging and RoHS compliance per EU Directive 2011/65/EU. The TO-263 package uses matte tin lead finish, and all materials meet TI's strict environmental specifications. Full compliance documentation, including test reports and substance declarations, is available via TI's Quality & Environmental page.
LM2679S-ADJ/NOPB 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:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.21V
- Voltage - Output (Max):
- 37V
- 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-ADJ/NOPB FAQ
1.How can I place an order for LM2679S-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679S-ADJ/NOPB 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-ADJ/NOPB reliable?
The price and inventory of LM2679S-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2679S-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2679S-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679S-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679S-ADJ/NOPB?
LM2679S-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679S-ADJ/NOPB 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-ADJ/NOPB?
For technical support, including LM2679S-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679S-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2679S-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679S-ADJ/NOPB 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-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679S-ADJ/NOPB?
All LM2679S-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679S-ADJ/NOPB, 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-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2679S-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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