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Texas Instruments LM2679SX-12/NOPB
- Part No.:
- LM2679SX-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2679SX-12/NOPB.pdf
- Description:
- IC REG BUCK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:2,847
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Product details
Overview
LM2679SX-12/NOPB from Texas Instruments is a monolithic 5-A step-down (buck) DC/DC voltage regulator with fixed 12-V output, 8–40-V input range, 260-kHz fixed-frequency PWM control, 120-mΩ DMOS high-side switch, and resistor-programmable current limit (5.5–7.6 A typical). It delivers >92% efficiency at 24-VIN/5-AOUT and targets industrial power supplies requiring stable, high-current regulation.
For engineers reviewing the LM2679SX-12/NOPB datasheet, LM2679SX-12/NOPB pinout, LM2679SX-12/NOPB application, or LM2679SX-12/NOPB equivalent, key selection considerations include its ±2% output tolerance over line/load/temperature, soft-start timing via external capacitor, thermal shutdown protection, and compatibility with standard off-the-shelf inductors and low-ESR output capacitors.
Technical Context
The LM2679SX-12/NOPB implements a fixed-frequency (260 kHz) voltage-mode PWM controller driving an integrated 120-mΩ DMOS high-side switch. Its feedback loop senses output voltage directly at the FB pin for fixed-output variants, eliminating external resistive dividers. Current limiting is set by an external resistor to the Current Adjust pin, establishing peak switch current per ICL = 37,125 / RADJ.
Operation requires a bootstrap capacitor (0.01 µF) between CB and Switch Output pins to sustain gate drive above VIN, and soft-start is controlled by a capacitor from SS to GND. The device operates across –40°C to +125°C junction temperature and integrates thermal shutdown and under-voltage lockout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±2% over full line, load, and temperature (–40°C to 125°C) |
| Input Voltage Range | 8 V to 40 V - supports wide industrial and battery-derived supplies |
| Max Output Current | 5 A continuous - enables single-chip solutions for mid-power systems |
| Switch RDS(ON) | 0.12 Ω typical at 25°C - minimizes conduction loss and improves efficiency |
| Oscillator Frequency | 260 kHz ±11% - enables use of compact magnetics and predictable EMI profile |
| Current Limit Range | 5.5 A to 7.6 A (typical) - programmable via external resistor for fault robustness |
| Efficiency | Up to 92% at VIN = 24 V, IOUT = 5 A - reduces thermal load and system cooling requirements |
Pinout & Package
LM2679SX-12/NOPB is packaged in a 7-pin TO-263 (KTW) surface-mount package with exposed thermal pad (10.10 mm × 8.89 mm), optimized for high-current thermal dissipation on PCB copper planes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Switch Output) | High-side MOSFET drain node | Switching node connected to inductor and Schottky diode cathode; carries high di/dt current |
| 2 (Input) | Main power supply input | Connects to 8–40 V source and high-frequency input bypass capacitors; shortest possible trace required |
| 3 (CB) | Bootstrap capacitor connection | Requires 0.01 µF ceramic capacitor to Switch Output pin to enable full gate drive for low RDS(ON) |
| 4 (GND) | Power ground reference | Common return for input/output capacitors and thermal pad; must be tied to low-impedance ground plane |
| 5 (Current Adjust) | Peak current limit programming | Resistor to GND sets ICL = 37,125 / RADJ; enables application-specific short-circuit protection |
| 6 (FB) | Feedback sense input | Internally connected to 12-V divider - direct connection to output required; no external resistors needed |
| 7 (SS) | Soft-start timing input | Capacitor to GND controls output voltage ramp rate; floating disables soft-start |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 120-mΩ DMOS switch | Eliminates need for external high-current MOSFET and driver, reducing BOM count and layout complexity |
| Resistor-programmable current limit | Enables precise tailoring of overcurrent protection without changing IC or layout - supports 3–7 A range |
| ±2% output voltage tolerance | Meets tight regulation requirements for sensitive analog or digital loads without post-regulation |
| 260-kHz fixed-frequency operation | Allows consistent filter design, predictable EMI filtering, and use of standardized inductor families |
| Thermal shutdown + UVLO | Provides autonomous fault recovery and prevents damage during abnormal input or thermal conditions |
Applications
| Industrial Power Supply | Battery Charger Pre-regulator |
|---|---|
Use Scenario: 24-V industrial bus powering PLC I/O modules and sensors requiring clean, regulated 12-V rails. IC Role / Device Role / Timing Role: Primary buck regulator delivering 5-A continuous 12-V output with high efficiency and thermal resilience. Use Value: 92% efficiency at 24-VIN/5-AOUT reduces heat sink size and improves system reliability in enclosed enclosures. | Use Scenario: Li-ion battery charger front-end converting variable 15–36-V adapter input to stable 12-V intermediate rail. IC Role / Device Role / Timing Role: Preregulator stage before linear or switching charge management IC, absorbing input transients and ripple. Use Value: Wide 8–40-V input range accommodates unregulated wall adapters and automotive sources; soft-start prevents inrush into downstream charging circuitry. |
| Embedded System Core Supply | Test Equipment Auxiliary Rail |
Use Scenario: FPGA or DSP carrier board requiring tightly regulated 12-V core supply with fast transient response. IC Role / Device Role / Timing Role: High-current point-of-load regulator with direct FB connection and minimal external components. Use Value: ±2% output tolerance ensures compliance with processor core voltage specifications; 260-kHz switching enables compact LC filter design. | Use Scenario: Benchtop test instrument needing isolated, low-noise 12-V auxiliary supply for analog front-end circuitry. IC Role / Device Role / Timing Role: Secondary regulated rail derived from main 48-V or 24-V system supply. Use Value: Integrated thermal shutdown and current limit protect sensitive measurement circuits during fault conditions; TO-263 package supports heatsinking for continuous 5-A operation. |
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/NOPB | Same pinout, identical 12-V fixed output, but rated for 3-A max output current and uses different internal current-sense architecture | Suitable only for ≤3-A loads; lacks resistor-programmable current limit - fixed at ~3.5 A | Select when lower cost and reduced thermal demand justify lower current capability |
| TPS54560DGQ | Adjustable output (0.8–36 V), 60-V max input, 5-A rating, but requires external compensation and has different pinout and soft-start behavior | Supports wider input range and flexible output tuning, but increases design complexity and component count | Select when input exceeds 40 V or output voltage adjustment is required beyond fixed 12 V |
Compared with LM2678-12/NOPB, LM2679SX-12/NOPB provides 67% higher current capacity and programmable fault protection; compared with TPS54560DGQ, it offers simpler implementation for fixed 12-V use cases but less flexibility in input/output configuration.
Availability
LM2679SX-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery charger pre-regulators, and embedded system core supplies requiring stable component supply, long-term manufacturability, and qualified thermal performance up to 125°C junction temperature.
Supply support for LM2679SX-12/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 ease-of-use, minimal external component count, and robust operation in industrial, automotive, and telecom power applications.
FAQ
What is the maximum input voltage rating for LM2679SX-12/NOPB?
The absolute maximum input voltage for LM2679SX-12/NOPB is 45 V, but the recommended operating range is 8 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger internal protection circuits. For sustained reliability, designs should maintain VIN ≤ 40 V under all conditions including transients and ripple.
Does LM2679SX-12/NOPB require external feedback resistors?
No, LM2679SX-12/NOPB does not require external feedback resistors. As a fixed 12-V output variant, it contains internal precision resistor dividers connected to the FB pin. The FB pin must be connected directly to the output capacitor's positive terminal to close the regulation loop - no external components are needed for voltage setting.
What is the purpose of the CB pin on LM2679SX-12/NOPB?
The CB (bootstrap capacitor) pin on LM2679SX-12/NOPB connects to a 0.01-µF ceramic capacitor tied to the Switch Output (pin 1). This forms a charge pump that elevates the gate drive voltage above VIN, ensuring full enhancement of the internal DMOS switch and maintaining low RDS(ON) across the input range - critical for achieving >92% efficiency.
Can LM2679SX-12/NOPB be used in parallel for higher current?
No, LM2679SX-12/NOPB is not designed for current-sharing or paralleling. Its fixed-frequency voltage-mode control lacks synchronization or current-sharing features. Attempting to parallel units may cause instability, unequal current distribution, or thermal runaway. For >5-A requirements, select a higher-current regulator or implement a discrete current-sharing scheme with external controllers.
What thermal performance can be expected from LM2679SX-12/NOPB in TO-263 package?
In the TO-263 (KTW) package with adequate PCB copper area (≥0.4896 in² of 1-oz copper), LM2679SX-12/NOPB achieves a junction-to-ambient thermal resistance (RθJA) of 35°C/W. At 5-A load and 24-V input, typical power dissipation is ~1.5 W, resulting in ~53°C junction rise above ambient - well within the –40°C to +125°C operating range when properly heatsinked.
LM2679SX-12/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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)
LM2679SX-12/NOPB FAQ
1.How can I place an order for LM2679SX-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2679SX-12/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 LM2679SX-12/NOPB reliable?
The price and inventory of LM2679SX-12/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2679SX-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2679SX-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2679SX-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2679SX-12/NOPB?
LM2679SX-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2679SX-12/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 LM2679SX-12/NOPB?
For technical support, including LM2679SX-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2679SX-12/NOPB requirements.
6.How does Aetrix verify that LM2679SX-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2679SX-12/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 LM2679SX-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2679SX-12/NOPB?
All LM2679SX-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2679SX-12/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 LM2679SX-12/NOPB part is unused and in its original packaging.
Return procedure for LM2679SX-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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