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Texas Instruments LM2679T-ADJ/NOPB
- Part No.:
- LM2679T-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2679T-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 5A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:194
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Product details
Overview
LM2679T-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 output current capability, 260-kHz fixed-frequency PWM control, and resistor-programmable peak current limit (5.5–7.6 A at 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 LM2679T-ADJ/NOPB datasheet, LM2679T-ADJ/NOPB pinout, LM2679T-ADJ/NOPB application, or LM2679T-ADJ/NOPB equivalent, key selection criteria include its ±2% output voltage tolerance over line/load/temperature, soft-start timing via external capacitor, feedback reference voltage of 1.21 V, and thermal shutdown with junction temperature range of –40°C to 125°C.
Technical Context
The LM2679T-ADJ/NOPB implements a voltage-mode PWM controller with internal 260-kHz oscillator driving a single high-side DMOS switch. Its feedback loop senses output voltage via an external resistor divider referenced to a 1.21-V internal bandgap, enabling precise regulation across 1.2 V–37 V. Current limiting is set by a resistor from the Current Adjust pin to GND, yielding ICL = 37,125 / RADJ.
Soft-start is implemented by charging an external capacitor on the SS pin to linearly ramp duty cycle; bootstrapping is handled via a 0.01-μF capacitor between CB and Switch_output pins. The device supports continuous conduction mode operation and includes thermal shutdown and overcurrent protection independent of load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output current | 5 A continuous - supports high-power loads without external current boosting |
| Input voltage range | 8 V to 40 V - compatible with 12 V/24 V industrial rails and wide-range battery inputs |
| Output voltage range | 1.2 V to 37 V adjustable - configured via external feedback resistors, not fixed |
| Oscillator frequency | 260 kHz ±11% - enables use of compact off-the-shelf inductors and reduces EMI compared to lower frequencies |
| Feedback reference | 1.21 V ±1.2% - sets output accuracy; used with resistor divider for precise VOUT programming |
| Switch RDS(ON) | 0.14 Ω max at 25°C - minimizes conduction loss and supports >90% efficiency at full load |
| Current limit range | 3 A to 7 A programmable - set by RADJ; 5.6 kΩ yields 5.5–7.6 A depending on temperature |
Pinout & Package
LM2679T-ADJ/NOPB is supplied in a 7-pin TO-263 (KTW) thermally enhanced surface-mount package with exposed DAP connected internally to Pin 4 (GND). Package dimensions are 10.10 mm × 8.89 mm × 4.83 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Switch_output) | High-side switch drain node | Swings between VIN and ~−0.5 V during OFF state; connects directly to inductor and Schottky diode cathode |
| 2 (Input) | Main power input | Accepts 8–40 V supply; requires low-ESR bypass capacitors placed adjacent to minimize switching noise |
| 3 (CB) | Bootstrap capacitor connection | Connects 0.01 μF ceramic capacitor to Switch_output to drive gate above VIN for full MOSFET enhancement |
| 4 (GND) | Power ground | Common return for input/output capacitors, thermal pad, and internal circuitry; must be low-inductance plane |
| 5 (Current_adjust) | Peak current limit programming | 1.21-V reference sink; RADJ to GND sets ICL = 37,125 / RADJ (e.g., 5.6 kΩ → ~6.3 A typ) |
| 6 (FB) | Feedback sense input | High-impedance input (85 nA bias) referenced to 1.21 V; connects to resistor divider midpoint for VOUT setting |
| 7 (SS) | Soft-start timing node | 3.7 μA current source charges external capacitor to linearly ramp output voltage; floating disables soft-start |
Key Features
| Feature | Design Value |
|---|---|
| Resistor-programmable current limit | Enables precise fault-current tailoring (3–7 A) without redesigning PCB layout or selecting new MOSFETs |
| Integrated 120-mΩ DMOS switch | Eliminates need for external high-current switch and associated gate-drive circuitry, reducing BOM count and footprint |
| 260-kHz fixed-frequency operation | Allows predictable EMI filtering and consistent inductor sizing using standardized off-the-shelf parts |
| ±2% output voltage tolerance | Ensures stable system-level voltage margins without post-regulation trimming or calibration |
| Thermal shutdown protection | Automatically disables switching when junction temperature exceeds safe operating limit, preventing permanent damage |
Applications
| Industrial Power Supply | Battery Charging System |
|---|---|
Use Scenario: Converting 24 V bus to 5 V/5 A for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary buck regulator providing regulated 5 V rail with tight line/load regulation and surge immunity. Use Value: Delivers 92% efficiency at full load, minimizing heat dissipation in enclosed enclosures without forced airflow. | Use Scenario: Charging 12 V sealed lead-acid batteries from variable solar or generator sources. IC Role / Device Role / Timing Role: Constant-voltage/constant-current preregulator stage controlling charge voltage up to 14.4 V. Use Value: Adjustable output and programmable current limit allow single design to support multiple battery chemistries and capacities. |
| Test Equipment Power Rail | Motor Drive Logic Supply |
Use Scenario: Generating clean, stable 3.3 V/5 A for FPGA configuration and ADC reference circuits. IC Role / Device Role / Timing Role: High-accuracy, low-noise intermediate regulator supplying sensitive analog/digital subsystems. Use Value: ±2% output tolerance and soft-start prevent logic glitches during power-up sequencing in automated test systems. | Use Scenario: Providing isolated 15 V gate drive supply for half-bridge MOSFET drivers in 24 V motor controllers. IC Role / Device Role / Timing Role: Robust pre-regulator delivering stable auxiliary rail despite high dv/dt noise from motor switching. Use Value: Wide 8–40 V input range accommodates battery voltage sag and surge transients without dropout or reset. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596T-ADJ/NOPB | 3-A output, 150-kHz switching, no programmable current limit, higher RDS(ON) (0.22 Ω) | Limited to lower-power loads; less suitable for 5-A continuous or high-efficiency designs | Select when cost sensitivity outweighs current capability and efficiency requirements |
| TPS54560DGQ | 5-A, 60-V input, 2.5-MHz switching, integrated compensation, no external current limit resistor | Higher frequency allows smaller magnetics; lacks analog current limit adjustability | Select when board space is constrained and programmable current limit is not required |
Compared with LM2596T-ADJ/NOPB, LM2679T-ADJ/NOPB delivers 67% higher output current and 10% higher efficiency at 5 A; versus TPS54560DGQ, it offers direct resistor-based current limit tuning but requires external compensation components and operates at lower frequency.
Availability
LM2679T-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charging systems, and test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LM2679T-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 with broad industrial and automotive reach.
The LM2679 series belongs to TI's SIMPLE SWITCHER® family of easy-to-design DC-DC regulators, engineered to simplify high-efficiency buck converter implementation using minimal external components and standard off-the-shelf magnetics.
FAQ
What is the maximum output voltage achievable with LM2679T-ADJ/NOPB?
The LM2679T-ADJ/NOPB supports an adjustable output voltage range from 1.2 V to 37 V, determined by the external feedback resistor divider. This upper limit is constrained by the absolute maximum rating of the FB pin (14 V) and internal reference stability-exceeding 37 V risks violating operational safety margins and is not characterized or guaranteed per the datasheet.
Can LM2679T-ADJ/NOPB operate with an input voltage below 8 V?
No. The LM2679T-ADJ/NOPB has a minimum recommended input voltage of 8 V per its Absolute Maximum Ratings and Recommended Operating Conditions. Operation below this threshold may result in improper startup, unstable regulation, or failure to maintain regulation due to insufficient headroom for the internal bias circuitry and DMOS switch drive.
How is the current limit set on LM2679T-ADJ/NOPB?
The current limit on LM2679T-ADJ/NOPB is set by connecting a resistor (RADJ) between the Current_adjust pin (Pin 5) and GND. The relationship is ICL = 37,125 / RADJ (in ohms), yielding 5.5–7.6 A typical at 5.6 kΩ. This resistor defines peak switch current before overcurrent shutdown activates, independent of load resistance or output voltage.
What package type is used for LM2679T-ADJ/NOPB?
LM2679T-ADJ/NOPB uses the 7-pin TO-263 (KTW) package-a thermally enhanced surface-mount variant with an exposed DAP connected to Pin 4 (GND). Its body size is 10.10 mm × 8.89 mm, optimized for high-power dissipation in compact layouts without requiring through-hole mounting.
Does LM2679T-ADJ/NOPB require an external bootstrap capacitor?
Yes. LM2679T-ADJ/NOPB requires a 0.01-μF ceramic capacitor connected between the CB pin (Pin 3) and Switch_output (Pin 1) to provide gate drive voltage above VIN for the internal DMOS switch. Omitting this capacitor prevents proper high-side FET enhancement and results in immediate failure to regulate or excessive power dissipation.
LM2679T-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-7 Formed Leads
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2679T-ADJ/NOPB FAQ
1.How can I place an order for LM2679T-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679T-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 LM2679T-ADJ/NOPB reliable?
The price and inventory of LM2679T-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 LM2679T-ADJ/NOPB is usually 5 days.
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Once your LM2679T-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 LM2679T-ADJ/NOPB?
For technical support, including LM2679T-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679T-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2679T-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679T-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 LM2679T-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679T-ADJ/NOPB?
All LM2679T-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679T-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 LM2679T-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2679T-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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