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Texas Instruments LM2679SD-ADJ/NOPB
- Part No.:
- LM2679SD-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 14-VDFN Exposed Pad
- Datasheet:
-
LM2679SD-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A 14VSON
- Quantity:
- Payment:
- Shipping:
Inventory:4,734
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Product details
Overview
LM2679SD-ADJ/NOPB from Texas Instruments is a monolithic step-down (buck) DC-DC regulator IC with adjustable output voltage (1.2 V to 37 V), 5-A continuous load capability, 260-kHz fixed-frequency PWM control, and resistor-programmable current limit (5.5 A typical at RADJ = 5.6 kΩ). It integrates a 120-mΩ DMOS high-side switch and operates from 8 V to 40 V input, targeting industrial power supplies and battery-charging systems.
For engineers reviewing the LM2679SD-ADJ/NOPB datasheet, LM2679SD-ADJ/NOPB pinout, LM2679SD-ADJ/NOPB application, or LM2679SD-ADJ/NOPB equivalent, key selection considerations include its adjustable feedback architecture, soft-start timing capacitor interface, bootstrap capacitor requirement, and thermal performance in TO-263-7 (KTW) package under high-current continuous operation.
Technical Context
The LM2679SD-ADJ/NOPB implements a voltage-mode PWM controller with internal 260-kHz oscillator, fixed-frequency operation, and external compensation via feedback divider. Its current-limit function is set by a resistor from Current Adjust (pin 5) to GND, establishing ICL = 37,125 / RADJ (A), enabling precise overcurrent protection without external sense resistors.
It uses a bootstrap capacitor (0.01 µF) between CB (pin 3) and Switch Output (pin 1) to drive the high-side DMOS gate above VIN, ensuring low RDS(ON) (0.12 Ω typical at 25°C). The FB (pin 6) input senses output voltage via external resistor divider, with VFB = 1.21 V ±1.2% over temperature, enabling stable regulation across 1.2 V–37 V output range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | 5 A continuous - supports high-power loads without external current amplification |
| Input voltage range | 8 V to 40 V - compatible with 12 V/24 V industrial rails and wide-range battery inputs |
| Switching frequency | 260 kHz ±11% - enables use of compact off-the-shelf inductors and reduces EMI filtering burden |
| Feedback reference | 1.21 V ±1.2% - sets output accuracy for adjustable configurations using standard resistor tolerances |
| RDS(ON) | 0.12 Ω (25°C) - minimizes conduction loss and thermal rise at full 5-A load |
| Current limit | 5.5 A typical (RADJ = 5.6 kΩ) - programmable over 3–7 A range to match system fault thresholds |
| Efficiency | 84% at VIN = 12 V, IOUT = 5 A - enables thermally constrained designs without forced air cooling |
Pinout & Package
LM2679SD-ADJ/NOPB is packaged in TO-263-7 (KTW) surface-mount package with exposed thermal pad (10.10 mm × 8.89 mm), optimized for high-current PCB thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch output | Drain node of internal DMOS FET; connects to inductor and Schottky diode cathode; switches between VIN and ~−0.5 V |
| 2 (VIN) | Input supply | Main power input (8–40 V); requires low-ESR bypass capacitors placed adjacent to minimize high-frequency noise |
| 3 (CB) | Bootstrap capacitor | Connects to SW via 0.01 µF ceramic capacitor to generate gate drive voltage > VIN for full FET enhancement |
| 4 (GND) | Power ground | Common return for input/output capacitors and thermal pad; must be tied to large copper area for thermal dissipation |
| 5 (IADJ) | Current limit adjust | Sets peak switch current via resistor to GND; ICL = 37,125 / RADJ (Ω) - e.g., 5.6 kΩ yields ~6.3 A |
| 6 (FB) | Feedback input | Senses output voltage divider midpoint; internal 1.21 V reference enables 1.2–37 V output programming |
| 7 (SS) | Soft-start | Controls output ramp rate via external capacitor; prevents inrush current; floating disables soft-start |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120-mΩ DMOS switch | Eliminates need for external high-current MOSFET and gate driver, reducing BOM count and layout complexity |
| Resistor-programmable current limit | Enables precise overcurrent protection tuning without current-sense resistors or additional ICs |
| 260-kHz fixed-frequency oscillator | Ensures predictable EMI profile and simplifies filter design versus variable-frequency alternatives |
| ±2% output tolerance over line/load/temp | Meets tight regulation requirements for sensitive analog or digital subsystems without post-regulation |
| Soft-start with external capacitor | Prevents input surge and output overshoot during power-up, critical for systems with large output capacitance |
Applications
| Industrial Power Supply | Battery Charger |
|---|---|
Use Scenario: 24-V input converted to 15-V/5-A rail for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated DC power; handles transient load steps up to 5 A with <100 mV undershoot. Use Value: 84% efficiency at full load reduces heatsink size; adjustable output supports multiple downstream voltage domains. | Use Scenario: Charging 12-V sealed lead-acid battery from 36-V solar array with constant-current/constant-voltage profile. IC Role / Device Role / Timing Role: Constant-current stage controller; current limit set via IADJ resistor to match battery C-rate; FB used for CV termination. Use Value: Resistor-programmable current limit eliminates need for external current-sense amplifier and op-amp circuitry. |
| Motor Drive Pre-regulator | Test Equipment Power Module |
Use Scenario: Generating 5-V/5-A bias rail for gate drivers and logic in a 48-V BLDC motor inverter. IC Role / Device Role / Timing Role: High-current preregulator upstream of linear LDOs; withstands 48-V transients per ISO 7637-2. Use Value: 40-V max input rating and thermal shutdown protect against automotive load-dump events without derating. | Use Scenario: Programmable 3.3–24-V output module in automated test equipment requiring fast voltage settling and low ripple. IC Role / Device Role / Timing Role: Adjustable output stage; SS pin controls ramp time to meet test sequence timing requirements. Use Value: 1.21-V precision reference and ±2% output tolerance enable accurate calibration without trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678SD-5.0/NOPB | Fixed 5-V output; no FB or IADJ pins; same package and 5-A rating | Lacks output adjustability and programmable current limit; suited only for fixed 5-V systems | Select when output voltage is fixed and design simplicity outweighs flexibility needs |
| TPS54560DGQR | 60-V input, 5-A, adjustable; 100–2500-kHz sync-capable; smaller 10-pin VSON | Higher input voltage range and frequency flexibility; requires external compensation network | Select for wider input range or EMI-sensitive designs needing spread-spectrum or synchronization |
Compared with LM2678SD-5.0/NOPB, LM2679SD-ADJ/NOPB provides output voltage and current limit configurability at the cost of two extra pins; compared with TPS54560DGQR, it offers simpler layout and integrated compensation but less input voltage headroom and frequency control.
Availability
LM2679SD-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery chargers, motor drive pre-regulators, and test equipment power modules requiring stable component supply and long-term manufacturability.
Supply support for LM2679SD-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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family of integrated DC-DC regulators, designed to simplify high-efficiency power supply design using minimal external components for industrial, automotive, and telecom applications.
FAQ
What is the maximum input voltage rating for LM2679SD-ADJ/NOPB?
The absolute maximum input voltage for LM2679SD-ADJ/NOPB is 45 V, with recommended operating range specified from 8 V to 40 V. Operation at 40 V ensures reliable performance across temperature extremes while maintaining thermal margin. Exceeding 40 V may trigger internal protection circuits or reduce lifetime reliability. Always verify input transient conditions (e.g., load dump) against this limit in final system design. LM2679SD-ADJ/NOPB includes built-in thermal shutdown and current limiting to prevent damage under overvoltage stress.
How do I set the output voltage of LM2679SD-ADJ/NOPB to 12 V?
To set LM2679SD-ADJ/NOPB to 12 V, connect a resistor divider from output to FB (pin 6) and FB to GND. With VFB = 1.21 V, use R1 = 8.93 kΩ (top) and R2 = 1.0 kΩ (bottom) for 12 V: VOUT = 1.21 × (1 + R1/R2). Place both resistors close to FB pin and avoid routing near inductor or SW node to prevent noise coupling. LM2679SD-ADJ/NOPB does not require external compensation for this configuration due to internal Type II compensation. Confirm stability with load-step testing per datasheet Figure 11.
What is the purpose of the CB pin on LM2679SD-ADJ/NOPB?
The CB (bootstrap capacitor) pin on LM2679SD-ADJ/NOPB connects to a 0.01 µF ceramic capacitor between CB and SW (pin 1) to generate gate drive voltage above VIN for the internal high-side DMOS switch. This ensures full enhancement of the FET, minimizing RDS(ON) and conduction losses. Without proper CB connection, the switch cannot turn on fully, causing excessive heating or failure to regulate. LM2679SD-ADJ/NOPB requires this external capacitor for normal operation - it is not optional. Use X7R or C0G dielectric with low ESR and place physically adjacent to pins 1 and 3.
Can LM2679SD-ADJ/NOPB operate in discontinuous conduction mode (DCM)?
Yes, LM2679SD-ADJ/NOPB operates in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM), automatically transitioning based on load current and inductor value. At light loads (<1 A), inductor current falls to zero each cycle, entering DCM - confirmed in datasheet Figure 10 and 12. DCM reduces light-load efficiency but improves transient response and eliminates subharmonic oscillation. LM2679SD-ADJ/NOPB does not require mode-selection pins or external circuitry to support DCM; it is inherent to its voltage-mode PWM architecture and fixed-frequency operation.
What thermal management is required for LM2679SD-ADJ/NOPB at 5-A load?
At 5-A continuous load with VIN = 12 V, LM2679SD-ADJ/NOPB dissipates ~0.75 W (based on RDS(ON) = 0.12 Ω and efficiency = 84%). In TO-263-7 (KTW) package with PCB copper area matching the die attach paddle, RθJA is 56°C/W; with 0.4896 in² copper (3.6× package area), it drops to 35°C/W. To maintain TJ < 125°C at 25°C ambient, ≥2 in² of 1-oz copper connected to the thermal pad via ≥6 thermal vias is recommended. LM2679SD-ADJ/NOPB includes thermal shutdown at ~165°C for protection. Monitor case temperature near the exposed pad during validation.
LM2679SD-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 14-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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:
- 14-VSON (5x6)
LM2679SD-ADJ/NOPB FAQ
1.How can I place an order for LM2679SD-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679SD-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 LM2679SD-ADJ/NOPB reliable?
The price and inventory of LM2679SD-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 LM2679SD-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2679SD-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679SD-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679SD-ADJ/NOPB?
LM2679SD-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679SD-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 LM2679SD-ADJ/NOPB?
For technical support, including LM2679SD-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679SD-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2679SD-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679SD-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 LM2679SD-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679SD-ADJ/NOPB?
All LM2679SD-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679SD-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 LM2679SD-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2679SD-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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